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Proportional Hazards (proportional + hazard)
Kinds of Proportional Hazards Terms modified by Proportional Hazards Selected AbstractsTests of Proportional Hazards and Proportional Odds Models for Grouped Survival DataBIOMETRICS, Issue 4 2000Enrico A. Colosimo Summary. In this paper, we derive score test statistics to discriminate between proportional hazards and proportional odds models for grouped survival data. These models are embedded within a power family transformation in order to obtain the score tests. In simple cases, some small-sample results are obtained for the score statistics using Monte Carlo simulations. Score statistics have distributions well approximated by the chi-squared distribution. Real examples illustrate the proposed tests. [source] Proportional hazards estimate of the conditional survival functionJOURNAL OF THE ROYAL STATISTICAL SOCIETY: SERIES B (STATISTICAL METHODOLOGY), Issue 4 2000Ronghui Xu We introduce a new estimator of the conditional survival function given some subset of the covariate values under a proportional hazards regression. The new estimate does not require estimating the base-line cumulative hazard function. An estimate of the variance is given and is easy to compute, involving only those quantities that are routinely calculated in a Cox model analysis. The asymptotic normality of the new estimate is shown by using a central limit theorem for Kaplan,Meier integrals. We indicate the straightforward extension of the estimation procedure under models with multiplicative relative risks, including non-proportional hazards, and to stratified and frailty models. The estimator is applied to a gastric cancer study where it is of interest to predict patients' survival based only on measurements obtained before surgery, the time at which the most important prognostic variable, stage, becomes known. [source] Comparing alternative models: log vs Cox proportional hazard?HEALTH ECONOMICS, Issue 8 2004Anirban Basu Abstract Health economists often use log models (based on OLS or generalized linear models) to deal with skewed outcomes such as those found in health expenditures and inpatient length of stay. Some recent studies have employed Cox proportional hazard regression as a less parametric alternative to OLS and GLM models, even when there was no need to correct for censoring. This study examines how well the alternative estimators behave econometrically in terms of bias when the data are skewed to the right. Specifically we provide evidence on the performance of the Cox model under a variety of data generating mechanisms and compare it to the estimators studied recently in Manning and Mullahy (2001). No single alternative is best under all of the conditions examined here. However, the gamma regression model with a log link seems to be more robust to alternative data generating mechanisms than either OLS on ln(y) or Cox proportional hazards regression. We find that the proportional hazard assumption is an essential requirement to obtain consistent estimate of the E(y,x) using the Cox model. Copyright © 2004 John Wiley & Sons, Ltd. [source] Comparison of models for genetic evaluation of survival traits in dairy cattle: a simulation studyJOURNAL OF ANIMAL BREEDING AND GENETICS, Issue 2 2008J. Jamrozik Summary Three models for the analysis of functional survival data in dairy cattle were compared using stochastic simulation. The simulated phenotype for survival was defined as a month after the first calving (from 1 to 100) in which a cow was involuntarily removed from the herd. Parameters for simulation were based on survival data of the Canadian Jersey population. Three different levels of heritability of survival (0.100, 0.050 and 0.025) and two levels of numbers of females per generation (2000 or 4000) were considered in the simulation. Twenty generations of random mating and selection (on a second trait, uncorrelated with survival) with 20 replicates were simulated for each scenario. Sires were evaluated for survival of their daughters by three models: proportional hazard (PH), linear multiple-trait (MT), and random regression (RR) animal models. Different models gave different ranking of sires with respect to survival of their daughters. Correlations between true and estimated breeding values for survival to five different points in a cow's lifetime after the first calving (120 and 240 days in milk after first, second, third and fourth calving) favoured the PH model, followed by the RR model evaluations. Rankings of models were independent of the heritability level, female population size and sire progeny group size (20 or 100). The RR model, however, showed a slight superiority over MT and PH models in predicting the proportion of sire's daughters that survived to the five different end-points after the first calving. [source] Statins Decrease Adverse Outcomes in Coronary Artery Bypass for Extensive Coronary Artery Disease as well as Left Main Coronary StenosisCARDIOVASCULAR THERAPEUTICS, Issue 2 2010Hui-Li Gan The aim of this study was to evaluate the effects of preoperative and postoperative statins on coronary artery bypass grafting (CABG) for extensive coronary artery disease as well as left main coronary stenosis (LMS). The data of 626 cases of extensive coronary artery disease as well as LMS patients in Anzhen Hospital between January 1998 and March 2008 for CABG procedure were retrospectively analyzed, and were classified as preoperative statin therapy group (Group A, n = 320) or preoperative no statin therapy group (Group B, n = 306). Propensity scores were estimated to determine the probability of inclusion into statin therapy group, resulting in the successful matching of 267 pairs. The incidence of in-hospital death, and atrial fibrillation or flutter and disabling stroke was higher in Group B than in Group A. The actuarial freedom from late events at 5 yrs were 98.75%± 0.73% for the postoperative statin therapy group and 88.33%± 3.71% for the postoperative no statin therapy group respectively, P= 0.000. The logistic regression revealed that CRP (>5.0 mg/L), and elevated Troponin I, and emergent procedure, and preoperative IABP support, and EF < 40% were the independent risk factors, and preoperatively statins was the protective factor for the perioperative death; and the Cox proportional hazard also revealed that preoperative IABP support and preoperative cardiac arrest, and EF < 40% were independent risk factors, and postoperatively statins were the protective factor for the late cardiac events. Preoperative statin therapy could provide protective effect in the perioperative period. Postoperative statin usage could provide protective effect on the late cardiac events. [source] Violence from young women involuntarily admitted for severe drug abuseACTA PSYCHIATRICA SCANDINAVICA, Issue 1 2007T. Palmstierna Objective:, To simultaneously evaluate actuarial and dynamic predictors of severe in-patient violence among women involuntarily admitted for severe drug abuse. Method:, All patients admitted to special facilities for involuntary treatment of absconding-prone, previously violent, drug abusing women in Sweden were assessed with the Staff Observation Aggression Scale, revised. Actuarial data on risk factors for violence were collected and considered in an extended Cox proportional hazards model with multiple events and daily assessments of the Broset Violence Checklist as time-dependent covariates. Results:, Low-grade violence and being influenced by illicit drugs were the best predictors of severe violence within 24 h. Significant differences in risk for violence between different institutions were also found. Conclusion:, In-patient violence risk is rapidly varying over time with being influenced by illicit drugs and exhibiting low-grade violence being significant dynamic predictors. Differences in violence between patients could not be explained by patient characteristics. [source] Evidence of shared genetic risk factors for migraine and rolandic epilepsyEPILEPSIA, Issue 11 2009Tara Clarke Summary Purpose:, Evidence for a specific association between migraine and rolandic epilepsy (RE) has been conflicting. Children with migraine frequently have electroencephalographic (EEG) abnormalities, including rolandic discharges, and approximately 50% of siblings of patients with RE exhibit rolandic discharges. We assessed migraine risk in RE probands and their siblings. Methods:, We used cohort and reconstructed cohort designs to respectively assess the relative risk of migraine in 72 children with RE and their 88 siblings using International Classification of Headache Disorders (ICHD-2) criteria. Incidences were compared in 150 age and geographically matched nonepilepsy probands and their 188 siblings. We used a Cox proportional hazards model, using age as the time base, adjusting hazard ratios (HRs) for sex in the proband analysis, and for sex and proband migraine status in the sibling analysis. Results:, Prevalence of migraine in RE probands was 15% versus 7% in nonepilepsy probands, and in siblings of RE probands prevalence was 14% versus 4% in nonepilepsy siblings. The sex-adjusted HR of migraine for an RE proband was 2.46 [95% confidence interval (CI) 1.06,5.70]. The adjusted HR of having ,1 sibling with migraine in an RE family was 3.35 (95% CI 1.20,9.33), whereas the HR of any one sibling of a RE proband was 2.86 (95% CI 1.10,7.43). Discussion:, Migraine is strongly comorbid in RE and independently clusters in their siblings. These results suggest shared susceptibility to migraine and RE that is not directly mediated by epileptic seizures. Susceptibility gene variants for RE may be tested as risk factors for migraine. [source] Recurrence after a First Unprovoked Cryptogenic/Idiopathic Seizure in Children: A Prospective Study from São Paulo, BrazilEPILEPSIA, Issue 2 2004Anna E. Scotoni Summary: Purpose: To evaluate the recurrence risk after a first unprovoked seizure in a large population of children and adolescents of a developing country. Methods: This prospective study was conducted at two tertiary hospitals, between September 1989 and August 1998. Children were enrolled if they had a first unprovoked cryptogenic/idiopathic seizure and maximal interval to the enrollment ,90 days. EEG and computed tomography (CT) were performed in most patients. Potential predictors of recurrence were compared by using the Cox proportional hazards model in univariate and multivariate analyses. Survival analysis was performed by using the Kaplan,Meier curves. Results: Two hundred thirteen children were included. Recurrence occurred in 34% of the patients, and mean time for recurrence was 12 months. Statistical analysis showed significance for seizure recurrence only for patients with abnormal EEGs. CT was performed in 182 patients, and abnormalities were found in 9.5%. Small calcifications were the most frequent finding, and this was not a predictor for recurrence. Conclusions: The risk of recurrence after a first unprovoked seizure in children from a developing country is similar to that found in developed countries. An abnormal EEG is a risk factor for seizure recurrence in children with a cryptogenic/idiopathic seizure. Calcifications on CT do not increase the risk of recurrence. [source] Treatment results of 1070 patients with nasopharyngeal carcinoma: An analysis of survival and failure patternsHEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 7 2005To-Wai Leung FRCR Abstract Background. The aim of this analysis was to evaluate the outcomes of patients with nasopharyngeal carcinoma (NPC) treated primarily by external beam irradiation (ERT) and to explore for possible ways to improve the treatment results. Methods. One thousand seventy patients with nonmetastatic NPC treated from 1990 to 1998 were retrospectively analyzed. The distribution according to the Union Internationale Contre le Cancer (UICC) (1997 edition) staging system at initial diagnosis was as follows: stage I, n = 113; stage IIA, n = 38; stage IIB, n = 360; stage III, n = 306; stage IVA, n = 136; stage IVB, n = 117; T1, n = 284; T2a, n = 88; T2b, n = 398; T3, n = 149; T4, n = 151; N0, n = 321; N1, n = 393; N2, n = 238; N3a, n = 29; N3b, n = 89. Two hundred eight patients were given neoadjuvant chemotherapy. Ninety-seven patients were diagnosed with locally persistent disease and were salvaged with high dose rate intracavitary brachytherapy. Multivariate analysis was performed with the Cox regression proportional hazards model. Results. The 5-year actuarial local failure,free survival, regional failure,free survival, distant metastasis,free survival, progression-free survival, cancer-specific survival, and overall survival rates were 80.9%, 93.3%, 77.2%, 62.7%, 71.4%, and 66.5%, respectively. Isolated distant metastasis occurred in 191 patients (18%). The distributions were as follow: stage I, 2.1% (two of 95); stage IIA, 5.7% (two of 35); stage IIB, 14.9% (45 of 302); stage III, 26.4% (62 of 235); stage IVA, 40% (40 of 100); stage IVB, 47.1% (40 of 85). Results of the multivariate analysis of various clinical endpoints were discussed. By studying these failure patterns, it is hoped that we could refine future treatments according to the failure patterns of patients with different risks of locoregional and distant failure. Conclusions. The 18% incidence of isolated distant metastasis is too high to be ignored. Maximizing the local control and minimizing the risk of distant metastasis and late complications should be the key objectives in designing future clinical trials. © 2005 Wiley Periodicals, Inc. Head Neck27: XXX,XXX, 2005 [source] Clusterin expression is associated with decreased disease-free survival of patients with colorectal carcinomasHISTOPATHOLOGY, Issue 7 2010Maximino Redondo Redondo M, Rodrigo I, Alcaide J, Tellez T, Roldan M J, Funez R, Diaz-Martin A, Rueda A & Jiménez E (2010) Histopathology,56, 932,936 Clusterin expression is associated with decreased disease-free survival of patients with colorectal carcinomas Aims:, It has been demonstrated that increased clusterin expression is involved in malignant progression and that anticlusterin treatment leads to selective apoptosis. The aim of this study was to determine the clinicopathological significance of clusterin expression in human colorectal carcinomas. Methods and results:, The expression of clusterin was examined in 31 adenomas and 103 colorectal carcinomas. Normal epithelial cells were always negative for clusterin expression, but clusterin expression was present in 16% (5/31) of adenomas and this percentage increased in colorectal carcinomas (30%, 31/103). Immunopositivity always presented an apical cytoplasmic pattern. The expression level of clusterin did not correlate with age, gender, grade or stage. However, its expression was significantly associated with a decrease in disease-free survival (P < 0.05). In a multivariate Cox proportional hazards model, clusterin expression remained a significant independent predictor. Conclusions:, Clusterin expression may have a role in colonic carcinogenesis and may help identify patients with more aggressive tumours who may benefit from targeted therapy. [source] Physical activity and risk of prostate cancer in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohortINTERNATIONAL JOURNAL OF CANCER, Issue 4 2009Nina Føns Johnsen Abstract The evidence concerning the possible association between physical activity and the risk of prostate cancer is inconsistent and additional data are needed. We examined the association between risk of prostate cancer and physical activity at work and in leisure time in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. In our study, including 127,923 men aged 20,97 years from 8 European countries, 2,458 cases of prostate cancer were identified during 8.5 years of followup. Using the Cox proportional hazards model, we investigated the associations between prostate cancer incidence rate and occupational activity and leisure time activity in terms of participation in sports, cycling, walking and gardening; a metabolic equivalent (MET) score based on weekly time spent on the 4 activities; and a physical activity index. MET hours per week of leisure time activity, higher score in the physical activity index, participation in any of the 4 leisure time activities, and the number of leisure time activities in which the participants were active were not associated with prostate cancer incidence. However, higher level of occupational physical activity was associated with lower risk of advanced stage prostate cancer (ptrend = 0.024). In conclusion, our data support the hypothesis of an inverse association between advanced prostate cancer risk and occupational physical activity, but we found no support for an association between prostate cancer risk and leisure time physical activity. © 2009 UICC [source] Reduction of TIP30 correlates with poor prognosis of gastric cancer patients and its restoration drastically inhibits tumor growth and metastasisINTERNATIONAL JOURNAL OF CANCER, Issue 3 2009Xiaohua Li Abstract Gastric cancer is an aggressive cancer with poor prognosis. Identification of precise prognostic marker and effective therapeutic target is important in the treatment of gastric cancer. TIP30, a newly identified tumor suppressor, appears to be involved in multiple functions including tumorigenic suppression, apoptosis induction and diminishing angiogenic properties. Here, the level of TIP30 expression was determined in gastric cancer, and the impact of its alteration on cancer biology and clinical outcome was investigated. We found that TIP30 protein was absent or reduced in gastric cancer cell lines. There was also a loss or substantial decrease of TIP30 expression in 106 cases of gastric tumors as compared with that in normal gastric mucosa (p < 0.05), which was significantly associated with inferior survival duration. In a Cox proportional hazards model, TIP30 expression independently predicted better survival (p < 0.05). We also restored TIP30 protein expression in human gastric cancer-derived cells AGS and MKN28 lacking endogenous TIP30 protein to study the effects of TIP30 expression on cell proliferation, cell kinetics, tumorigenicity and metastasis in BALB/c nude mice and found that adenoviral-mediated restoration of TIP30 expression led to downregulation of cyclin D1, Bcl-2, Bcl-xl, but to upregulation of p27, Bax, p53, caspase 3 and 9 expression, cell cycle G0/G1 arrest and apoptosis in vitro, and dramatic attenuation of tumor growth and abrogation of metastasis in animal models. Taken together, the present work revealed a novel function of TIP30, which can possibly be used as an independent prognostic factor and a potential therapeutic target for gastric cancer. © 2008 Wiley-Liss, Inc. [source] Nonsteroidal anti-inflammatory drugs and the risk of developing breast cancer in a population-based prospective cohort study in Washington County, MDINTERNATIONAL JOURNAL OF CANCER, Issue 1 2007Lisa Gallicchio Abstract The objective of this study was to examine the association between nonsteroidal anti-inflammatory drug (NSAID) use and the development of breast cancer, and to assess whether this association differed by estrogen receptor (ER) subtype. Data were analyzed from 15,651 women participating in CLUE II, a cohort study initiated in 1989 in Washington County, MD. Medication data were collected at baseline in 1989 and in 1996. Incident cases of invasive breast cancer occurring from baseline to March 27, 2006 were identified through linkage of cohort participants with the Washington County Cancer Registry and the Maryland State Cancer Registry. Cox proportional hazards modeling was used to calculate the risk ratios (RR) and 95% confidence intervals (95% CI) for breast cancer associated with medication use. Among women in the CLUE II cohort, 418 invasive breast cancer cases were identified during the follow-up period. The results showed that self-reported use of NSAIDs in both 1989 and in 1996 was associated with a 50% reduction in the risk of developing invasive breast cancer compared with no NSAID use in either 1989 or 1996 (RR = 0.50; 95% CI 0.28, 0.91). The protective association between NSAID use and the risk of developing breast cancer was consistent among ER-positive and ER-negative breast cancers, although only the RR for ER-positive breast cancer was statistically significant. Overall, findings from this study indicate that NSAID use is associated with a decrease in breast cancer risk and that the reduction in risk is similar for ER-positive and ER-negative tumors. © 2007 Wiley-Liss, Inc. [source] Brain cancer mortality and potential occupational exposure to lead: Findings from the National Longitudinal Mortality Study, 1979,1989INTERNATIONAL JOURNAL OF CANCER, Issue 5 2006Edwin van Wijngaarden Abstract We evaluated the association between potential occupational lead exposure and the risk of brain cancer mortality in the National Longitudinal Mortality Study (NLMS), which is a prospective census-based cohort study of mortality among the noninstitutionalized United States population (1979,1989). The present study was limited to individuals for whom occupation and industry were available (n = 317,968). Estimates of probability and intensity of lead exposure were assigned using a job-exposure matrix (JEM). Risk estimates for the impact of lead on brain cancer mortality were computed using standardized mortality ratio (SMR) and proportional hazards and Poisson regression techniques, adjusting for the effects of age, gender and several other covariates. Brain cancer mortality rates were greater among individuals in jobs potentially involving lead exposure as compared to those unexposed (age- and gender-adjusted hazard ratio (HR) = 1.5; 95% confidence interval (CI) = 0.9,2.3) with indications of an exposure,response trend (probability: low HR = 0.7 (95% CI = 0.2,2.2), medium HR = 1.4 (95% CI = 0.8,2.5), high HR = 2.2 (95% CI = 1.2,4.0); intensity: low HR = 1.2 (95% CI = 0.7,2.1), medium/high HR = 1.9 (95% CI = 1.0,3.4)). Brain cancer risk was greatest among individuals with the highest levels of probability and intensity (HR = 2.3; 95% CI = 1.3,4.2). These findings provide further support for an association between occupational lead exposure and brain cancer mortality, but need to be interpreted cautiously due to the consideration of brain cancer as one disease entity and the absence of biological measures of lead exposure. © 2006 Wiley-Liss, Inc. [source] Cigarette smoking, elevated fasting serum glucose, and risk of pancreatic cancer in Korean menINTERNATIONAL JOURNAL OF CANCER, Issue 1 2006Ji Eun Yun Abstract Pancreatic cancer is one of the most fatal human cancers and continues to be a major unsolved health problem. The goal of this study was to estimate the independent effects and interactions between cigarette smoking and diabetes on the risk of pancreatic cancer in Korean male population. Cigarette smoking and the risk of incidence and death from pancreatic cancer were examined in a 10-year prospective cohort study of 446,407 Korean men aged 40 to 65 years who received health insurance from the National Health Insurance Corporation and who had a medical evaluation in 1992. Relative risks (RR) and 95% confidence intervals (CI) were calculated using a Cox proportional hazards model after adjusting for age, body mass index, exercise and alcohol use. Current smoking was associated with an increased risk of incidence (RR = 1.7, 95% CI = 1.6,1.9) and mortality (RR = 1.6, 95% CI = 1.4,1.7) from pancreatic cancer. The RR for pancreatic cancer increased with both duration and amount of smoking. Diabetes was also associated with an increased risk of both incidence (RR = 1.8, 95% CI = 1.5,2.2) and mortality (RR = 1.7, 95% CI = 1.4,2.1) from pancreatic cancer. There was no interaction between smoking and fasting serum glucose in terms of pancreatic cancer risk. Thus, our prospective study has demonstrated that cigarette smoking and elevated fasting serum glucose are independently associated with an increased risk of pancreatic cancer in a large cohort of Korean males. © 2006 Wiley-Liss, Inc. [source] Fruits and vegetables and renal cell carcinoma: Findings from the European prospective investigation into cancer and nutrition (EPIC)INTERNATIONAL JOURNAL OF CANCER, Issue 12 2006Steffen Weikert Abstract We examined the association between fruits and vegetables and risk of renal cell carcinoma (RCC) in the European Prospective Investigation into Cancer and Nutrition (EPIC). Dietary intake data and complete follow-up information on cancer incidence were available for 375,851 participants recruited in EPIC centers of 8 countries. During an average follow-up of 6.2 years, 306 incident cases of RCC were identified. The associations of consumption of total vegetables, total fruits, combined total fruits and vegetables and specific subtypes of vegetables with RCC risk were analyzed using Cox proportional hazards, stratified by centre and adjusted for potential confounders. No significant associations between fruit and vegetable consumption and RCC risk were observed despite a wide range of intake. The estimated relative risks (95% confidence intervals [CI]) in men and women combined were 0.97 (0.85,1.11) per 40 g increase in vegetable intake, 1.03 (0.97,1.08) per 40 g increase in fruit intake and 1.02 (0.93,1.11) per 80 g increase in fruit and vegetable intake combined. Among the vegetable subtypes, an inverse association was observed for root vegetables (RR per 8 g increase: 0.88; 95% CI: 0.78,0.99). These results suggest that total consumption of fruits and vegetables is not related to risk of RCC, although we cannot exclude the possibility that very low consumption is related to higher risk. The relationship of specific fruit and vegetable subgroups with RCC risk warrant further investigation. © 2006 Wiley-Liss, Inc. [source] Angiopoietin-2 expression in breast cancer correlates with lymph node invasion and short survivalINTERNATIONAL JOURNAL OF CANCER, Issue 4 2003Christian Sfiligoi Abstract Angiogenic factors produced by tumor cells are essential for tumor growth and metastasis. In our study, the expression of Angiopoietin-1 (ANG1) and Angiopoietin-2 (ANG2) mRNA in archival human breast cancer tumor samples and in 6 breast cancer cell lines was investigated. Total RNA from biopsies of 38 breast cancer patients was extracted and ANG1 and ANG2 mRNA expression was measured by means of quantitative real-time RT-PCR (Taqman®). Matching data with available clinicopathologic and biochemical data revealed a significant association between ANG2 expression and axillary lymph node invasion. Univariate and multivariate survival analysis, by means of Kaplan-Meier method and Cox's proportional hazards model, showed significant and independent association between ANG2 mRNA level and both disease-free (p < 0.0001) and overall survival (p < 0.0003). An important fact is that, notwithstanding the small number of cases examined, this association was confirmed also in the group of lymph node-negative patients (DFS, p < 0.003; OS, p < 0.020). Immunohistochemical analysis demonstrated that Ang2 is expressed by both tumor cells and endothelial elements. Expression in tumor cells was confirmed by studying a panel of human breast carcinoma cell lines in culture by RT-PCR. In ZR75.1 and T47D cells, expression of ANG2 mRNA was increased up to 10-fold by treatment with estrogen within 24 hr. Although preliminary, these data suggest a possible role of ANG2 as a prognostic factor for primary breast cancer. © 2002 Wiley-Liss, Inc. [source] The effect of economic deprivation on oesophageal and gastric cancer in a UK cancer networkINTERNATIONAL JOURNAL OF CLINICAL PRACTICE, Issue 6 2009J. A. Gossage Summary Aims:, The National Health Service (NHS) Cancer Plan aims to eliminate economic inequalities in healthcare provision and cancer outcomes. This study examined the influence of economic status upon the incidence, access to treatment and survival from oesophageal and gastric cancer in a single UK cancer network. Methodology:, A total of 3619 patients diagnosed with either oesophageal or gastric cancer in a London Cancer Network (population = 1.48 million) were identified from the Thames Cancer Registry (1993,2002). Patients were ranked into economic quintiles using the income domain of the Multiple Index of Deprivation. Statistical analysis was performed using a ,2 test. Survival analysis was performed using a Cox's proportional hazards model. Results:, Between 1993,1995 and 2000,2002, the incidence of oesophageal cancer in the most affluent males rose by 51% compared with a 2% rise in the least affluent males. The incidence of gastric cancer in most affluent males between 1993,1995 and 2000,2002 fell by 32% compared with a 7% fall in the least affluent males. These changes were less marked in females. Economic deprivation had no effect on the proportion of patients undergoing either resectional surgery or chemotherapy; the least affluent oesophageal cancer patients with a higher incidence of squamous cell carcinoma received significantly more radiotherapy. Economic deprivation had no effect upon survival for either oesophageal or gastric cancer. Conclusions:, There has been an increase in oesophageal cancer and a decrease in gastric cancer incidence among more affluent males in the last 10 years. Economic status did not appear to influence access to treatment or survival. [source] Depression status as a reliable predictor of functional decline among Japanese community-dwelling older adults: a 12-year population-based prospective cohort studyINTERNATIONAL JOURNAL OF GERIATRIC PSYCHIATRY, Issue 11 2009Hajime Iwasa Abstract Objective This study aimed to examine a longitudinal relationship between depression status and functional decline among Japanese community-dwelling older adults, using a 12-year population-based, prospective cohort study design. Method A total of 710 men and women, aged 65 years and over, participated in the study. Katz's Index and the Tokyo Metropolitan Institute of Gerontology Index of Competence were used to measure the functional capacities of basic activities of daily living (BADL) and higher-level competence, respectively. For the purpose of analysis, a decline in each subscale of functional capacity during the follow-up period were used as outcome variables; depression status assessed by the Japanese version of the 30-item Geriatric Depression Scale (GDS), with a cut-off of 11, was used as an independent variable; and age, gender, education level, history of chronic disease, hospitalization, smoking, physical activity, living alone, hearing problems, physical pain, dietary habits, and usual walking speed at baseline were used as covariates. Results Use of the multivariate Cox proportional hazards model adjusted for potential confounders showed that depression status was significantly and independently associated with BADL decline (risk ratio (RR),=,1.46, 95% confidence interval (CI): 1.13,1.89) and with higher-level competence decline (RR,=,1.56, 95% CI: 1.18,2.04). Conclusion Our study found an independent relationship between depression status and longitudinal change in functional capacity among community-dwelling older individuals, suggesting that depression status is a reliable predictor of functional decline (both of BADL decline and higher-level competence decline) in older adults. Copyright © 2009 John Wiley & Sons, Ltd. [source] Physical Performance and Subsequent Disability and Survival in Older Adults with Malignancy: Results from the Health, Aging and Body Composition StudyJOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 1 2010Heidi D. Klepin MD OBJECTIVES: To evaluate objective physical performance measures as predictors of survival and subsequent disability in older patients with cancer. DESIGN: Longitudinal cohort study. SETTING: Health, Aging and Body Composition (Health ABC) Study. PARTICIPANTS: Four hundred twenty-nine individuals diagnosed with cancer during the first 6 years of follow-up of the Health ABC Study. MEASUREMENTS: The associations between precancer measures of physical performance (20-m usual gait speed, 400-m long-distance corridor walk (LDCW), and grip strength) and overall survival and a short-term outcome of 2-year progression to disability or death were evaluated. Cox proportional hazards and logistic regression models, stratified for metastatic disease, respectively, were used for outcomes. RESULTS: Mean age was 77.2, 36.1% were women, and 45.7% were black. Faster 20-m usual walking speed was associated with a lower risk of death in the metastatic group (hazard ratio=0.89, 95% confidence interval (CI)=0.79,0.99) and lower 2-year progression to disability or death in the nonmetastatic group (odds ratio (OR)=0.77, 95% CI=0.64,0.94). Ability to complete the 400-m LDCW was associated with lower 2-year progression to disability or death in the nonmetastatic group (OR=0.24, 95% CI=0.10,0.62). There were no associations between grip strength and disability or death. CONCLUSION: Lower extremity physical performance tests (usual gait speed and 400-m LDCW) were associated with survival and 2-year progression to disability or death. Objective physical performance measures may help inform pretreatment evaluations in older adults with cancer. [source] A Pilot Study of Banxia Houpu Tang, a Traditional Chinese Medicine, for Reducing Pneumonia Risk in Older Adults with DementiaJOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 12 2007Koh Iwasaki MD OBJECTIVES: To evaluate whether the traditional Chinese herbal medicine Banxia Houpu Tang (BHT, formula magnolia et pinelliae) prevents aspiration pneumonia and pneumonia-related mortality in elderly people. DESIGN: A prospective, observer-blinded, randomized, controlled trial. SETTING: Two long-term care hospitals for handicapped elderly patients in Japan from March 2005 to February 2006. PARTICIPANTS: One hundred four elderly patients (31 men and 73 women; mean age±standard deviation 83.5±7.8) with dementia and cerebrovascular disease, Alzheimer's disease, or Parkinson's disease. INTERVENTION: Ninety-five participants (mean age 84.0, M:F=28:67) were randomly assigned to the BHT treatment group (n=47) or the control group (n=48) and took BHT or placebo for 12 months. MEASUREMENTS: The occurrence of pneumonia, mortality due to pneumonia, and the daily amount of self-feeding. RESULTS: Complete data were available for analysis on 92 of the 95 subjects randomized. Four patients in the BHT group developed pneumonia, and one of them died as a result. Fourteen patients in the control group developed pneumonia, and six of them died as a result. There was a significant difference between the two groups in pneumonia onset (P=.008), and a tendency toward significance in pneumonia-related mortality (P=.05). The relative risk of pneumonia in the BHT group compared with the control group was 0.51 (95% confidence interval (CI)=0.27,0.84, P=.008) and that of death from pneumonia was 0.41 (95% CI=0.10,1.03, P=.06) according to the Cox proportional hazards model. No adverse events were observed from treatment with BHT. The BHT group was able to maintain self-feeding better than the control group (P=.006). CONCLUSION: Treatment with BHT reduced the risk of pneumonia and pneumonia-related mortality in elderly patients with dementia. [source] Change in Motor Function and Risk of Mortality in Older PersonsJOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 1 2007Aron S. Buchman MD OBJECTIVES: To assess the association between change in motor function and mortality. DESIGN: Prospective, observational cohort study. SETTING: Approximately 40 retirement communities across the Chicago metropolitan area participating in the Rush Memory and Aging Project. PARTICIPANTS: Eight hundred thirty-seven community-based older persons without dementia. MEASUREMENTS: Change in composite measures of motor performance and muscle strength. RESULTS: During a mean follow-up of 2.2 years, 81 persons died. In a proportional hazards model adjusted for age, sex, education, and body mass index, each 1-unit increase in the level of baseline motor performance was associated with an approximately 10% decrease in risk of mortality (hazard ratio (HR)=0.901, 95% confidence interval (CI)=0.863,0.941), and each unit of annual increase in motor performance was associated with an approximately 11% decrease in the risk of mortality (HR=0.887, 95% CI=0.835,0.942). In a similar model, each 1-unit increase in the level of baseline strength was associated with an approximately 9% decrease in the risk of mortality (HR=0.906, 95% CI=0.859,0.957), and each 1-unit annual increase in strength was associated with an approximately 10% decrease in the risk of mortality (HR=0.898, 95% CI=0.809,0.996). These results were similar when men and women were analyzed separately and after controlling for physical activity, cognition, and chronic disorders. When motor performance and muscle strength were examined in a single model, only baseline and annual change in motor performance were associated with mortality. CONCLUSION: Level and rate of change in strength and motor performance are associated with mortality. The attenuation of the association between strength and mortality by motor performance suggests that motor function is not a unitary process and that its components may vary in their associations with adverse health consequences in older persons. [source] Cognitive Impairment and Mortality in Older Primary Care PatientsJOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 7 2001Timothy E. Stump MA OBJECTIVE: To assess the impact of cognitive impairment on mortality in older primary care patients after controlling for confounding effects of demographic and comorbid chronic conditions. DESIGN: Prospective cohort study. SETTING: Academic primary care group practice. PARTICIPANTS: Three thousand nine hundred and fifty-seven patients age 60 and older who completed the Short Portable Mental Status Questionnaire (SPMSQ) during routine office visits. MEASUREMENTS: Cognitive impairment measured at baseline using the SPMSQ, demographics, problem drinking, history of smoking, clinical data (including weight, cholesterol level, and serum albumin), and comorbid chronic conditions collected at baseline; survival time measured during the 5 to 7 years after baseline. RESULTS: Eight hundred and eighty-six patients (22.4%) died during the 5 to 7 years of follow-up. Cognitive impairment was categorized as having no impairment (84.3%), mild impairment (10.5%), and moderate-to-severe impairment (5.2%) based on SPMSQ score. Chi-square tests revealed that patients with moderate-to-severe impairment were significantly more likely to die compared with patients with mild impairment (40.8% vs 21.5%) and those with no impairment (40.8% vs 21.4%). No significant difference in crude mortality was found between patients with no impairment and those with mild impairment. After analyzing time to death using the Kaplan-Meier method, patients with moderate-to-severe cognitive impairment were at increased risk of death compared with those with no or mild impairment (Log-rank ,2 = 55.5; P < .0001). Even in multivariable analyses using Cox proportional hazards to control for confounding factors, compared with those with no impairment, moderately-to-severely impaired patients had an increased risk of death, with a hazard ratio (HR) of 1.70. Increased risk of death was also associated with older age (HR = 1.03 for each year), a history of smoking (HR = 1.48), having a serum albumin level <3.5 g/L (HR = 1.29), and weighing less than 90% of the ideal body weight (HR = 1.98). Outpatient diagnoses associated with increased mortality risk were diabetes mellitus, coronary artery disease, congestive heart failure, cerebrovascular disease, cancer, anemia, and chronic obstructive pulmonary disease (HR range 1.36,1.67). Factors protective of mortality risk included female gender (HR = 0.67) and black race (HR = 0.73). CONCLUSIONS: Moderate-to-severe cognitive impairment is associated with an increased risk of mortality, even after controlling for confounding effects of demographic and clinical characteristics. Mild cognitive impairment is not associated with mortality risk, but a longer follow-up period may be necessary to identify this risk if it exists. [source] Bayesian inference in a piecewise Weibull proportional hazards model with unknown change pointsJOURNAL OF ANIMAL BREEDING AND GENETICS, Issue 4 2007J. Casellas Summary The main difference between parametric and non-parametric survival analyses relies on model flexibility. Parametric models have been suggested as preferable because of their lower programming needs although they generally suffer from a reduced flexibility to fit field data. In this sense, parametric survival functions can be redefined as piecewise survival functions whose slopes change at given points. It substantially increases the flexibility of the parametric survival model. Unfortunately, we lack accurate methods to establish a required number of change points and their position within the time space. In this study, a Weibull survival model with a piecewise baseline hazard function was developed, with change points included as unknown parameters in the model. Concretely, a Weibull log-normal animal frailty model was assumed, and it was solved with a Bayesian approach. The required fully conditional posterior distributions were derived. During the sampling process, all the parameters in the model were updated using a Metropolis,Hastings step, with the exception of the genetic variance that was updated with a standard Gibbs sampler. This methodology was tested with simulated data sets, each one analysed through several models with different number of change points. The models were compared with the Deviance Information Criterion, with appealing results. Simulation results showed that the estimated marginal posterior distributions covered well and placed high density to the true parameter values used in the simulation data. Moreover, results showed that the piecewise baseline hazard function could appropriately fit survival data, as well as other smooth distributions, with a reduced number of change points. [source] Bone Loss, Weight Loss, and Weight Fluctuation Predict Mortality Risk in Elderly Men and WomenJOURNAL OF BONE AND MINERAL RESEARCH, Issue 8 2007Nguyen D Nguyen Abstract Low baseline BMD, rate of BMD loss, weight loss, and weight fluctuation are significant predictors of all-cause mortality in elderly men and women, independent of each other and of age, incident fracture, and concomitant diseases. Introduction: Although low BMD has been shown to be associated with mortality in women, the effect of BMD is affected by weight and weight change and the contribution of these factors to mortality risk, particularly in men, is not known. This study examined the association between baseline BMD, rate of bone loss, weight loss, and weight fluctuation and all-cause mortality risk in elderly men and women. Materials and Methods: Data from 1059 women and 644 men, ,60 years of age (as of 1989), of white background who participated in the Dubbo Osteoporosis Epidemiology Study were analyzed. All-cause mortality was recorded annually between 1989 and 2004. BMD at the femoral neck was measured by DXA (GE-LUNAR) at baseline and at approximately every 2 yr afterward. Data on incident osteoporotic fractures and concomitant diseases, including cardiovascular diseases, all types of cancer, and type I/II diabetes mellitus, was also recorded. Results: In the multivariable Cox's proportional hazards model with adjustment for age, incident fractures, and concomitant diseases, the following variables were independent risk factors of all-cause mortality in men: rate of BMD loss of at least 1%/yr, rate of weight loss of at least 1%/yr, and weight fluctuation (defined by the CV) of at least 3%. In women, in addition to the significant factors observed in men, lower baseline BMD was also an independent risk factor of mortality. In both sexes, baseline weight was not an independent and significant predictor of mortality risk. Approximately 36% and 22% of deaths in women and men, respectively, were attributable to the four risk factors. Conclusions: These data suggest that, although low BMD was a risk factor of mortality in women, it was not a risk factor of mortality in men. However, high rates of BMD loss, weight loss, and weight fluctuation were also independent predictors of all-cause mortality in elderly men and women, independent of age, incident fracture, and concomitant diseases. [source] Incidence and Predictors of Sudden Cardiac Death in Patients with Diastolic Heart FailureJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 12 2007M.H.S., SANA M. AL-KHATIB M.D. Introduction: Although it is known that patients with diastolic heart failure are at an increased risk of death, their mode of death has not been clearly defined. We conducted this study to examine the incidence and predictors of sudden cardiac death (SCD) in patients with isolated diastolic heart failure. Methods and Results: Using the Duke Databank for Cardiovascular Disease, we identified patients with a history of congestive heart failure (CHF) and an ejection fraction of greater than 50% who were enrolled in the database from 1995 through 2004. Mode of death was adjudicated by two independent reviewers. Of the 1,941 patients who met our inclusion criteria, 548 (28%) died (40 were SCD). Using a Cox proportional hazards model, five variables were found to be independently associated with a significant increase in the risk of SCD. These variables include diabetes mellitus (P < 0.01), the presence of mild mitral regurgitation (P < 0.01), severity of CHF (P < 0.01), the occurrence of a myocardial infarction within 3 days prior to the date of the index cardiac catheterization (P = 0.01), and severity of coronary artery disease (P = 0.02). Conclusions: SCD is not uncommon in patients with isolated diastolic heart failure. We identified some clinical variables that are associated with a significant increase in the risk of SCD and that may be used in the risk stratification of patients for SCD. Studies are needed to validate our findings. [source] Effects of a tropical cyclone on the distribution of hatchery-reared black-spot tuskfish Choerodon schoenleinii determined by acoustic telemetryJOURNAL OF FISH BIOLOGY, Issue 3 2010Y. Kawabata The effects of a tropical cyclone on the distribution of hatchery-reared black-spot tuskfish Choerodon schoenleinii were examined using acoustic telemetry. Nine fish were released in Urasoko Bay, Ishigaki Island, Japan, in September 2006, and another nine were released in June to July 2007, before a cyclone's passing through the area in September 2007. Data for the fish released in 2006 were used as the cyclone-inexperienced group to compare their distribution pattern to that of the 2007 cyclone-experienced group. Both groups of fish were monitored for up to 150 days. Of the nine fish in each group, four (44%) and two (22%) were monitored for over 150 days in the cyclone-inexperienced and the cyclone-experienced groups, respectively. Three of the five fish that had settled in the monitoring area left the area within a few days of the cyclone event. To estimate the time of disappearance of the fish, maximum wind speed during a period of 7 days (indicating the occurrence and intensity of the tropical cyclone), fish size and release year were evaluated as explanatory variables using a Cox proportional hazards model with Akaike's information criterion. The best predictive model included the effect of maximum wind speed. One fish that left the monitoring area displayed movement patterns related to strong winds, suggesting that wind-associated strong currents swept the fish away. No relationships were found between the movement patterns of the other two fish and any physical environmental data. The daily detection periods of one of the two fish gradually decreased after the cyclone hit, and this fish eventually left the monitoring area within 3 days, suggesting that it shifted to a habitat outside the monitoring area. These results indicate that tropical cyclones have both direct and indirect effects on the distribution of hatchery-reared C. schoenleinii. [source] On the evolution of statistical methods as applied to clinical trialsJOURNAL OF INTERNAL MEDICINE, Issue 5 2004D. Machin Abstract. This paper describes how statistical methods have evolved in parallel with activities associated with randomized control trials. In particular we emphasize the pivotal role of two papers published in British Journal of Cancer, and the paper describing the Cox proportional hazards model. In addition, the importance of early papers on estimating the sample size required for trials is highlighted. Later developments including the increasing roles for competing risks, multilevel modelling and Bayesian methodologies are described. The interplay between computer software and statistical methodological developments is stressed. Finally some future directions are indicated. [source] Estimating the effect of treatment in a proportional hazards model in the presence of non-compliance and contaminationJOURNAL OF THE ROYAL STATISTICAL SOCIETY: SERIES B (STATISTICAL METHODOLOGY), Issue 4 2007Jack Cuzick Summary., Methods for adjusting for non-compliance and contamination, which respect the randomization, are extended from binary outcomes to time-to-event analyses by using a proportional hazards model. A simple non-iterative method is developed when there are no covariates, which is a generalization of the Mantel,Haenszel estimator. More generally, a ,partial likelihood' is developed which accommodates covariates under the assumption that they are independent of compliance. A key feature is that the proportion of contaminators and non-compliers in the risk set is updated at each failure time. When covariates are not independent of compliance, a full likelihood is developed and explored, but this leads to a complex estimator. Estimating equations and information matrices are derived for these estimators and they are evaluated by simulation studies. [source] Microparticle-associated tissue factor activity: a link between cancer and thrombosis?JOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 3 2007M. E. T. TESSELAAR Summary. Background:,Cancer, in particular mucinous adenocarcinoma, is associated with venous thromboembolism (VTE). Tissue factor (TF), initiator of coagulation, plays a central role in the paradigm that clotting and tumor growth form a vicious circle, in which hypercoagulability facilitates the aggressive biology of cancer and vice versa. Expression of TF in tumors is associated with poor differentiation and poor prognosis. Patient/methods:,We investigated the association between clinically manifest VTE and procoagulant properties of circulating microparticles (MP) isolated from blood of unselected pancreatic and breast adenocarcinoma patients' consecutive subjects, who presented with ultrasound or CT-scan confirmed VTE, and healthy subjects. Results:,Patients with disseminated breast and pancreatic cancer had significantly increased levels of MP-associated TF activity compared with healthy controls, subjects with idiopathic acute VTE and non-metastatic cancer patients. Patients with both high MP-associated TF-activity and MP-associated epithelial mucin (MUC1) had a lower survival rate at 3,9 months follow-up than those with low TF-activity and no MUC1 expression: the likelihood of survival was 0.42 (95% CI: 0.19, 0.94) for an individual with these two predictor variables present, after adjustment for other factors (age cohort, type of cancer, VTE) in the Cox proportional hazards model. Conclusions:,Our results suggest an important role for MP-associated TF and MUC1 in the pathogenesis of thrombosis in disseminated mucinous adenocarcinoma patients. Future studies should reveal the mechanism underlying the observed associations. [source] | ||||||||||||||||||||||||||||||||||||||||||||||