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Chi-squared Test (chi-squared + test)
Selected Abstractsp -Phenylenediamine sensitization is more prevalent in central and southern European patch test centres than in Scandinavian: results from a multicentre studyCONTACT DERMATITIS, Issue 6 2009Jacob Pontoppidan Thyssen Background:, Positive patch test reactions to p -phenylenediamine (PPD) are common. PPD is used in oxidative hair dyes and is also present in dark henna temporary ,tattoos'. Cross-sensitization to other contact allergens may occur. Because subjects sensitized to PPD are at risk of clinically severe reactions upon hair dyeing, there is a need for ,current' prevalence data on PPD sensitization. Objectives:, To compare PPD patch test results from dermatitis patients tested between 2003 and 2007 in 10 European patch test centres and to analyse the causes and determine relevance of positive PPD patch test reactions. Materials:, Patch testing was performed using PPD (1% free base in petrolatum from Trolab (Almirall Hermal GmbH, Reinbeck, Germany) or Chemotechnique (Malmö, Sweden), equivalent to 0.090 mg/cm2 in the TRUE® test from MEKOS Laboratories AS). Statistical analysis was performed using the chi-squared test. Results:, The weighted average prevalence was 4.6% among 21 515 patients. PPD sensitization occurred more often in centres located in Central and Southern Europe than in Scandinavian centres (odds ratio = 2.40; 95% confidence interval = 2.07,2.78). The overall proportion of positive patch test reactions to PPD that were registered as being of either current or ,past' relevance was high (weighted average 53.6% and 20.3%, respectively). Consumer hair dyeing was the most prominent cause of PPD sensitization (weighted average 41.8%). Furthermore, occupational hair dye exposure (10.6%) and cross-sensitization to textile dyes (12.6%) were frequently reported. Conclusions:, PPD sensitization caused by exposure to hair dyes is frequent and remains a present problem for patients visiting contact dermatitis clinics, especially in patch test centres located in Central and Southern Europe. [source] Medical association rule mining using genetic network programmingELECTRONICS & COMMUNICATIONS IN JAPAN, Issue 2 2008Kaoru Shimada Abstract An efficient algorithm for building a classifier is proposed based on an important association rule mining using genetic network programming (GNP). The proposed method measures the significance of the association via the chi-squared test. Users can define the conditions of important association rules for building a classifier flexibly. The definition can include not only the minimum threshold chi-squared value, but also the number of attributes in the association rules. Therefore, all the extracted important rules can be used for classification directly. GNP is one of the evolutionary optimization techniques, which uses the directed graph structure as genes. Instead of generating a large number of candidate rules, our method can obtain a sufficient number of important association rules for classification. In addition, our method suits association rule mining from dense databases such as medical datasets, where many frequently occurring items are found in each tuple. In this paper, we describe an algorithm for classification using important association rules extracted by GNP with acquisition mechanisms and present some experimental results of medical datasets. © 2008 Wiley Periodicals, Inc. Electron Comm Jpn, 91(2): 46,54, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10022 [source] Home Hemodialysis: Associations with Modality FailureHEMODIALYSIS INTERNATIONAL, Issue 1 2003BA Young Purpose: To determine risk factors for home hemodialysis (HH) failure. Methods: We conducted a prospective study from 12/2000 to 9/2002 using data from the 1709 patients who received renal replacement therapy at the Northwest Kidney Centers (NWKC). Prevalent and incident Home Hemodialysis (HH) patients were included in the analysis. Baseline demographics, date of entry and date of exit from HH were ascertained for all patients. Differences among groups were assessed by independent t-test for continuous variables and by chi-squared test for categorical variables. Risk of HH failure was assessed with logistic regression. Results: Of the 116 patients who initiated training in the NWKC HH program (6.8%), 77.7% remained in the HH program, 10.3% received a transplant and 10.3% returned to in-center dialysis. Compared to patients who received a transplant or returned to in-center dialysis, HH patients were more likely to be older (65 vs. 54 yrs, P < .05) and were on dialysis longer (3.8 ± 4.7 vs. 2.3 ± 3.0 yrs, p < 0.05). Ethnicity, gender, primary renal disease and helper status were similar between groups, and were not associated with increased risk of HH failure. Unadjusted 3-year mortality was 31.7% for HH patients. HH patients who died were more likely to be older (p < 0.05) and to have diabetes (P < 0.01) than those who returned to in-center dialysis or who received a transplant. Conclusions: In HH patients, older age but not ethnicity, gender or helper status was associated with treatment failure. Older age and diabetes remain risk factors for mortality in the HH population. [source] Intraoral condition in children with juvenile idiopathic arthritis compared to controlsINTERNATIONAL JOURNAL OF PAEDIATRIC DENTISTRY, Issue 6 2008EVA LEKSELL Aims. The aims of this study were to compare the periodontal conditions in children and adolescents with juvenile idiopathic arthritis (JIA) in comparison to age-matched healthy individuals, and to describe intraoral health in relation to medical assessments. Design. Forty-one JIA patients, 10,19 years old, were compared to 41 controls. Plaque, calculus, probing depth, bleeding on probing, clinical attachment loss, as well as mucosal lesions were registered. Marginal bone level was recorded on radiographs. A questionnaire was included. Data were analysed with chi-squared test, Fisher's exact test, and Mann,Whitney U -test (P < 0.05). Results. The JIA patients reported pain from jaws (P = 0.001), hands (P = 0.001), and oral ulcers (P = 0.015) more often than controls. They avoided certain types of food because of oral ulcers (P = 0.037). The frequencies of sites with plaque (32% vs. 19%, P = 0.013), calculus (11% vs. 5%, 5 = 0.034), bleeding on probing (26% vs. 14%, P < 0.01), and probing depth 2 mm (32% vs. 2%, P < 0.001) were higher among JIA patients. No sites with attachment loss or reduced marginal bone level were observed. Conclusions. These obtained results are probably because of joint pain, making it difficult to perform oral hygiene as well as the use of medication and general disease activity. [source] Accuracy of patient recall of preoperative symptom severity (angina and breathlessness) at one year following aorta-coronary artery bypass graftingJOURNAL OF CLINICAL NURSING, Issue 3 2009Grace M Lindsay Aim and objective., The accuracy with which patients recall their cardiac symptoms prior to aorta-coronary artery bypass grafting is assessed approximately one year after surgery together with patient-related factors potentially influencing accuracy of recall. Background., This is a novel investigation of patient's rating of preoperative symptom severity before and approximately one year following aorta-coronary artery bypass grafting. Design., Patients undergoing aorta-coronary artery bypass grafting (n = 208) were recruited preoperatively and 177 of these were successfully followed up at 16·4 (SD 2·1) months after surgery and asked to describe current and recalled preoperative symptoms using a 15-point numerical scale. Method., Accuracy of recall was measured and correlated (Pearson's correlation) with current and past symptoms, health-related quality of life and coronary artery disease risk factors. Hypothesis tests used Student's t -test and the chi-squared test. Results., Respective angina and breathlessness scores were recalled accurately by 16·9% and 14·1% while 59% and 58% were inaccurate by more than one point. Although the mean preoperative and recalled scores for severity of both angina and breathlessness and were not statistically different, patients who recalled most accurately their preoperative scores had, on average, significantly higher preoperative scores than those with less accurate recall. Patients whose angina and breathlessness symptoms were relieved by operation had significantly better accuracy of recall than patients with greater levels of symptoms postoperatively. Conclusion., Patient's rating of preoperative symptom severity before and one year following aorta-coronary artery bypass grafting was completely accurate in approximately one sixth of patients with similar proportions of the remaining patients overestimating and underestimating symptoms. The extent to which angina and breathlessness was relieved by operation was a significant factor in improving accuracy of recall. Relevance to clinical practice., Factors associated with accuracy of recall of symptoms provide useful insights for clinicians when interpreting patients' views of the effectiveness of aorta-coronary artery bypass grafting for the relief of symptoms associated with coronary heart disease. [source] Endoscopic sonographic evaluation of the thickened gallbladder wall in patients with acute hepatitisJOURNAL OF CLINICAL ULTRASOUND, Issue 5 2003Moon Young Kim MD Abstract Purpose. Thickening of the gallbladder wall is often observed during abdominal sonographic examination in patients with acute hepatitis. However, there is rarely an opportunity for a histopathologic analysis of these structural changes. Endoscopic sonography (EUS) can accurately delineate the structure of the gallbladder wall and therefore may be useful for visualizing changes in the gallbladder wall in patients with acute hepatitis. Hence, we prospectively studied the ability of EUS to detect specific structural changes in the gallbladder wall in patients with acute hepatitis and examined the effect of high elevation of serum liver enzyme levels on the gallbladder wall. Methods. A study group of patients diagnosed with acute hepatitis who had gallbladder wall thickening and a control group of patients without acute hepatitis or gallbladder disease underwent EUS between May 1, 1999, and June 1, 2002. EUS was used to measure the thickness of the gallbladder wall and to visualize each of its layers. Serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels of the patients with acute hepatitis were measured at the time of the EUS examination. Statistically significant differences were determined using an independent t test and the chi-squared test. A p value of less than 0.05 was considered statistically significant. Results. The acute hepatitis group comprised 28 men and 24 women with a mean age of 40.8 years. The control group comprised 25 men and 25 women with a mean age of 45.1 years. The mean gallbladder wall thickness ± standard deviation in the acute hepatitis group (6.3 ± 2.6 mm) was significantly greater than that in the control group (1.6 ± 0.4 mm; p < 0.01). The mean thickness of the gallbladder wall for patients in whom both the AST and the ALT levels were 500 U/l or higher (7.0 ± 2.6 mm) was significantly greater than that for patients with levels below 500 U/l (5.4 ± 2.3 mm; p < 0.05). In the acute hepatitis group, EUS showed thickened, well-defined muscular and serosal layers of the gallbladder wall in 24 of the patients and a diffusely thickened gallbladder wall, in which each layer was ill defined, in the other 28 patients. The mean thickness of the gallbladder wall for patients with the pattern of ill-defined layers was significantly greater than that for the patients with the pattern of well-defined layers (p < 0.05). The pattern of ill-defined layers was more common among patients in whom the serum AST and ALT levels were at least 500 U/l than among patients with levels below 500 U/l (p < 0.05). Conclusions. We propose that gallbladder wall thickening in patients with acute hepatitis is associated with prominent changes in the muscular and serosal layers. Patients with highly elevated serum liver enzyme levels are more likely to have gallbladder wall thickening and disruption of planes between the muscular and serosal layers than are patients with normal liver enzyme levels. © 2003 Wiley Periodicals, Inc. J Clin Ultrasound 31:245,249, 2003 [source] Is there a correlation between vaginal chlamydia infection and cervical smear abnormalities?JOURNAL OF OBSTETRICS AND GYNAECOLOGY RESEARCH (ELECTRONIC), Issue 1 2006A community-based study in the Al-Ain district, United Arab Emirates Abstract Aim:, The purpose of this study was to determine the correlation between vaginal chlamydia infection and cervical abnormalities. The data on the prevalence of chlamydia infection and cervical abnormalities have been presented elsewhere and in this article we provide the results of a correlation analysis. Methods:, In this cross-sectional, community-based survey, women attending primary and secondary care in the Al-Ain medical district, United Arab Emirates, were offered cervical screening using the Papanicolaou smear, and chlamydia testing. A total of 793 women underwent cervical screening and 728 were tested for chlamydia. A commercially available kit was used to determine the prevalence of chlamydia. The correlation between cervical abnormalities and chlamydia infection was tested using the chi-squared test or Fisher's exact test, as appropriate. Results:, The prevalence of abnormal smears was 1.51% (95% confidence interval [CI], 0.66,2.4). Twelve subjects had abnormal smears, including smears showing atypical squamous cells of undetermined significance. The prevalence of chlamydia infection in this population was 2.5% (95% CI, 1.2,3.3). Statistical analysis showed no association (,2 0.6, P = 0.4) between the prevalence of chlamydia infection and cervical abnormalities. Conclusion:, Although there have been earlier reports of an association between vaginal chlamydia and cervical abnormalities, our study does not provide evidence to support this association. [source] Effect of the Amount of Hours Spent Studying on the Prevalence of Overactive Bladder in College WomenLUTS, Issue 2 2010Dong Gil SHIN Objectives: We conducted a questionnaire survey to access whether the amount of hours spent studying has an effect on the prevalence of OAB in college women. Methods: A total of 126 (63%; mean: 23.2 years) of 200 women participants completed the questionnaire. They were divided into two groups: group A (weekly studying hour >40 h) consisted of medical female students and group B (weekly studying hour <25 h) consisted of French literature woman students. The factors related to OAB were analyzed by the chi-squared test. Results: Of 126 respondents, the prevalence of OAB was prevalent in 38 (30.2%) women. There was significant difference in prevalence between the two groups: 7.0% for group A and 42.2% for group B. In group B, OAB prevalence was 66.7% for ,2 h, 41.2% for 2,,4 h, 46.5% for 4,,6 h, and >6 h was 23.5%. This survey showed that there is no relationship between the amount of hours spent studying and OAB. Conclusion: Although the amount of hours spent studying had no association with OAB in college women, OAB prevalence showed a decreasing pattern as the quantity of studying hour increases. Consequently, it is thought that the attitude toward study has more association with OAB than the quantity of studying hours. [source] Prevalence of risk factors for statin-induced myopathy in rheumatoid arthritis patientsMUSCULOSKELETAL CARE, Issue 1 2010Tracey E. Toms MBChB MRCP Abstract Objectives:,Statins are widely prescribed in patients with rheumatoid arthritis (RA). Although statins offer overwhelming cardiovascular benefits, their use can be associated with the development of a statin-induced myopathy. Several factors increase the risk of developing statin-induced myopathy, including the single nucleotide polymorphism (SNP) rs4149056, located within the gene encoding solute carrier organic anion transporter (SLCO1B1). We aimed to identify the frequency of risk factors for statin-induced myopathy and establish whether the rs4149056 genotype is more prevalent in RA. Methods:,A total of 396 RA patients and 438 non-RA controls were studied. DNA samples were obtained from all patients. The SNP rs4149056 was identified using real-time polymerase chain reaction and melting curve analysis. Genotypic and allelic frequencies were calculated using the chi-squared test. Results:,Almost 80% of RA patients had one or more risk factor (range 1,5) for the development of statin-induced myopathy. Of the 74 RA patients treated with statins, 90% had one or more (range 1,4) risk factors. No differences in genotype or allelic frequencies were observed between RA patients and controls. Conclusions:,RA patients harbour multiple risk factors for statin-induced myopathy. However, the frequency of the rs4149056 genotypes does not differ according to the presence of RA. Despite this, no cases of statin-induced myopathy were observed in this cohort over a period of four years of follow-up. Thus, we conclude that statin use among RA patients is probably safe, but large-scale prospective studies are needed to confirm this. In the meantime, it may be good practice systematically to consider and record myopathy risk factors in these patients. Copyright © 2009 John Wiley & Sons, Ltd [source] Oral mucositis in acute lymphoblastic leukaemia: analysis of 169 paediatric patientsORAL DISEASES, Issue 8 2008SLC Figliolia Chemotherapy-induced oral mucositis is a frequent therapeutic challenge in cancer patients. The purpose of this retrospective study was to estimate the prevalence and risk factors of oral mucositis in 169 acute lymphoblastic leukaemia (ALL) patients treated according to different chemotherapeutic trials at the Darcy Vargas Children's Hospital from 1994 to 2005. Demographic data, clinical history, chemotherapeutic treatment and patients' follow-up were recorded. The association of oral mucositis with age, gender, leucocyte counts at diagnosis and treatment was assessed by the chi-squared test and multivariate regression analysis. Seventy-seven ALL patients (46%) developed oral mucositis during the treatment. Patient age (P = 0.33), gender (P = 0.08) and leucocyte counts at diagnosis (P = 0.34) showed no correlation with the occurrence of oral mucositis. Multivariate regression analysis showed a significant risk for oral mucositis (P = 0.009) for ALL patients treated according to the ALL-BFM-95 protocol. These results strongly suggest the greater stomatotoxic effect of the ALL-BFM-95 trial when compared with Brazilian trials. We concluded that chemotherapy-induced oral mucositis should be systematically analysed prospectively in specialized centres for ALL treatment to establish the degree of toxicity of chemotherapeutic drugs and to improve the quality of life of patients based on more effective therapeutic and prophylactic approaches for prevention of its occurrence. [source] Adjuvant chemotherapy for stage C colonic cancer in a multidisciplinary settingANZ JOURNAL OF SURGERY, Issue 10 2009Pierre H. Chapuis Abstract Background:, In this study of patients undergoing adjuvant chemotherapy for clinicopathological stage C colonic cancer after optimal surgery, the aims were: to describe their immediate experience of chemotherapy, to assess disease-free survival, to compare overall survival with that of a matched untreated historical control group, and to evaluate the associations between previously identified adverse risk factors and survival. Methods:, Data were drawn from a comprehensive, prospective hospital registry of resections for colorectal cancer between 1971 and 2004, with retrospective data on adjuvant chemotherapy. The main end point was overall survival. Statistical analysis employed the chi-squared test, Kaplan,Meier estimation and proportional hazards regression. Results:, From May 1992 to December 2004, there were 104 patients who received adjuvant chemotherapy. Duration of treatment, withdrawal from treatment, toxicity and other immediate treatment outcomes were similar to those in other equivalent studies. There were no toxicity-associated deaths. Overall survival was significantly longer in the treated patients than in the control group (3-year rates 81% and 66%, respectively, P = 0.009). A significant protective effect of adjuvant therapy was found (hazard ratio 0.5, 95% confidence interval 0.3,0.8, P = 0.001) after adjustment for histopathology features previously shown to be negatively associated with survival (high grade, venous invasion, apical node metastasis, free serosal surface involvement). Conclusions:, For patients who have had a curative resection for lymph node positive colonic cancer in a specialist colorectal surgical unit and been managed by a multidisciplinary team, post-operative adjuvant chemotherapy is safe and provides the same survival advantage as seen in randomized trials. [source] A Comparison of the Three Conditional Exact Tests in Two-way Contingency Tables Using the Unconditional Exact PowerBIOMETRICAL JOURNAL, Issue 3 2004Seung-Ho Kang Abstract The conditional exact tests of homogeneity of two binomial proportions are often used in small samples, because the exact tests guarantee to keep the size under the nominal level. The Fisher's exact test, the exact chi-squared test and the exact likelihood ratio test are popular and can be implemented in software StatXact. In this paper we investigate which test is the best in small samples in terms of the unconditional exact power. In equal sample cases it is proved that the three tests produce the same unconditional exact power. A symmetry of the unconditional exact power is also found. In unequal sample cases the unconditional exact powers of the three tests are computed and compared. In most cases the Fisher's exact test turns out to be best, but we characterize some cases in which the exact likelihood ratio test has the highest unconditional exact power. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Incorporating Correlation for Multivariate Failure Time Data When Cluster Size Is LargeBIOMETRICS, Issue 2 2010L. Xue Summary We propose a new estimation method for multivariate failure time data using the quadratic inference function (QIF) approach. The proposed method efficiently incorporates within-cluster correlations. Therefore, it is more efficient than those that ignore within-cluster correlation. Furthermore, the proposed method is easy to implement. Unlike the weighted estimating equations in Cai and Prentice (1995,,Biometrika,82, 151,164), it is not necessary to explicitly estimate the correlation parameters. This simplification is particularly useful in analyzing data with large cluster size where it is difficult to estimate intracluster correlation. Under certain regularity conditions, we show the consistency and asymptotic normality of the proposed QIF estimators. A chi-squared test is also developed for hypothesis testing. We conduct extensive Monte Carlo simulation studies to assess the finite sample performance of the proposed methods. We also illustrate the proposed methods by analyzing primary biliary cirrhosis (PBC) data. [source] The histological extent of the local spread of carcinoma of the penis and its therapeutic implicationsBJU INTERNATIONAL, Issue 3 2000A. Agrawal Objective,To explore the possibility of reducing the margin of clearance at surgery for carcinoma of the penis without causing an increase in the incidence of local tumour recurrence, so that the functional and cosmetic compromise associated with penectomy might be minimized. Patients and methods,Sixty-four patients underwent partial or total penectomy based on the extent of tumour. The specimens were evaluated histologically for grade and for proximal microscopic extensions beyond the grossly visible tumour margin, by examining serial proximal 5 mm sections. The histological grade of the lesion was correlated with its clinical site, morphology and proximal microscopic spread. Differences were assessed using the chi-squared test. Results,Of 64 tumours, 31% were grade 1, 50% grade 2 and the remaining 19% grade 3. Higher grade lesions were more likely to involve the penile shaft. The maximum proximal histological extent was 5 mm for grades 1 and 2, and 10 mm for grade 3 tumours; there was no discontinuous spread. Conclusions,Histological grading is mandatory in the management of carcinoma of the penis. A 10-mm clearance is adequate for grade 1 and 2 lesions, and 15 mm for grade 3 tumours. This approach would qualify more patients for partial rather than total amputation; the residual length of the penis would then be cosmetically and functionally more acceptable. [source] Do life- or school-satisfaction and self-esteem indicators explain the oral hygiene habits of schoolchildren?COMMUNITY DENTISTRY AND ORAL EPIDEMIOLOGY, Issue 5 2007S. Honkala Abstract,,, Objectives:, The aim of this study was to ascertain how frequently toothbrushing and flossing are practiced among schoolchildren in Kuwait and whether life- and school-satisfaction and self-esteem indicators are associated with oral hygiene habits. Methods:, A sample of 2312 schoolchildren between 11 and 13 years old filled out a structured questionnaire anonymously in school classrooms during 2002 and 2003. For this study, nationally representative samples of children were drawn from all six governorates of Kuwait. Only government schools were included. The questionnaire of the Health Behaviour in School-Aged Children Study was used in this study after it was modified to suit Kuwait. A chi-squared test and logistic regression model were used for analyzing the data. Results:, Over half of the pupils reported brushing their teeth more than once a day; girls reported brushing more frequently than boys did. One-fifth of the pupils did not brush their teeth even on a daily basis. The life- and school-satisfaction and self-esteem indicators were associated with more-than-once-a-day toothbrushing frequency. The strongest predictors for recommended brushing were: feeling very happy (OR 2.0, 95% CI 1.38,2.77), feeling that other pupils always accept him/her (1.5; 1.16,2.02), never/sometimes feeling lonely and feeling that it is very easy to make friends (1.4; 1.06,1.94). The summary variables of life-satisfaction, school-satisfaction and self-esteem seemed to be strongly associated with brushing. Dental floss was never used by 45% of the children, weekly by 18% and daily by 17%; 20% did not even know what dental floss was. Conclusions:, Among intermediate schoolchildren in Kuwait, oral hygiene practices were far behind the international recommendations. Special emphasis should be placed on children who have personal problems with their life, school and self-esteem. [source] Risk factors for oral hairy leukoplakia in HIV-infected adults of BrazilJOURNAL OF ORAL PATHOLOGY & MEDICINE, Issue 6 2006Mariela Dutra Gontijo Moura Background:, Oral hairy leukoplakia (OHL) may be an indicator of the progression of Human Immunodeficiency Virus (HIV)-induced immuno-depression, and the evaluation of risk factors leading to OHL is important in the management of these HIV-infected patients. However, there are few studies that analyze risk factors leading to OHL in the Brazilian population. The aim of this case,control study is to present data about prevalence rates and risk factors leading to OHL in a sample of HIV-infected adults in Brazil. Methods:, This case,control study included 111 HIV-infected patients treated at a clinic for sexually transmitted diseases and HIV. In the initial examinations with dentists, variables were collected from all patients. Diagnosis of OHL was performed in accordance with the International Classification System and cytological features. The Fisher and the chi-squared tests were used for statistical analysis. The proportional prevalence and odds ratio were estimated. Results:, Outcome presented a positive, statistically significant association among the presence of OHL and viral load of 3000 copies/,l or greater (P = 0.0001; odds ratio (OR) = 5.8), presence of oral candidiasis (P = 0.0000; OR = 11.1), previous use of fluconazole (P = 0.0000; OR = 24.6), and use of systemic acyclovir (P = 0.032; OR = 4.3). Antiretroviral medication presented a negative, statistically significant association with the presence of OHL (P = 0.002; OR = 8.4). Conclusions:, Prevalence of OHL was 28.8%. Viral load, oral candidiasis, previous use of fluconazole, and systemic acyclovir were determined to be risk factors for OHL. Antiretroviral medication proved to be protective against the development of OHL. [source] | |||||||||||||