			Home About us Contact

Important Confounder (important + confounder)

Distribution by Scientific Domains

Medical Sciences	80%

Selected Abstracts

Hospice Usage by Minorities in the Last Year of Life: Results from the National Mortality Followback Survey

JOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 7 2003
K. Allen Greiner MD
OBJECTIVES: To examine racial/ethnic variations in rates of hospice use in a national cohort and to identify individual characteristics associated with hospice use. DESIGN: Secondary analysis of the 1993 National Mortality Followback Survey (NMFS), a nationally obtained sample using death certificates and interviews with relatives (proxy respondents) to provide mortality, social, and economic data and information about healthcare utilization in the last year of life for 23,000 deceased individuals. SETTING: Hospice care. PARTICIPANTS: Individuals aged 15 and older who died in 1993. Subjects were included in this analysis if they died of nontraumatic causes (N = 11,291). MEASUREMENTS: Hospice use was dichotomized by proxy responses indicating use or nonuse of home or inpatient hospice services. The percentage of individuals using hospice services in the last year of life was calculated. RESULTS: Unadjusted bivariate results found that African Americans were less likely to use hospice than whites (odds ratio (OR) = 0.59; P < .001) and that those without a living will (LW) (OR = 0.23; P < .001) and without a cancer diagnosis (OR = 0.28; P < .001) were less likely to use hospice. The negative relationship between African Americans and hospice use was unaffected when controlled for sex, education, marital status, existence of a LW, income, and access to health care. Logistic models revealed that presence of a LW diminished the negative relationship between African Americans and hospice use, but the latter remained significant (OR = 0.83; P = .033). A subanalysis of subjects aged 55 and older showed a significant interaction between access to care and race/ethnicity with respect to hospice use (P = .044). Inclusion of income in this multivariable logistic model attenuated the relationship between African-American race/ethnicity and hospice use (OR = 0.77), and the difference between whites and African Americans became only marginally statistically significant (P = .060). CONCLUSION: In the 1993 NMFS, hospice use was negatively associated with African-American race/ethnicity independent of income and access to healthcare. The relationship is not independent of age, insurance type, or history of stroke. For subjects aged 55 and older, access to healthcare may be an important confounder of the negative relationship between African-American race/ethnicity and hospice use. Consistent with previous studies, this analysis found that African Americans were less likely to use LWs than whites. The reduced importance of African-American race/ethnicity on hospice use with the inclusion of presence of a LW in logistic models suggests that similar cultural processes may shape differences between African Americans and whites in advance care planning and hospice use. [source]

A parallel analysis of individual and ecological data on residential radon and lung cancer in south-west England

JOURNAL OF THE ROYAL STATISTICAL SOCIETY: SERIES A (STATISTICS IN SOCIETY), Issue 1 2001
Sarah Darby
Parallel individual and ecological analyses of data on residential radon have been performed using information on cases of lung cancer and population controls from a recent study in south-west England. For the individual analysis the overall results indicated that the relative risk of lung cancer at 100 Bq m,3 compared with at 0 Bq m,3 was 1.12 (95% confidence interval (0.99, 1.27)) after adjusting for age, sex, smoking, county of residence and social class. In the ecological analysis substantial bias in the estimated effect of radon was present for one of the two counties involved unless an additional variable, urban,rural status, was included in the model, although this variable was not an important confounder in the individual level analysis. Most of the methods that have been recommended for overcoming the limitations of ecological studies would not in practice have proved useful in identifying this variable as an appreciable source of bias. [source]

Weaknesses of goodness-of-fit tests for evaluating propensity score models: the case of the omitted confounder,

PHARMACOEPIDEMIOLOGY AND DRUG SAFETY, Issue 4 2005
Sherry Weitzen PhD
Abstract Purpose Propensity scores are used in observational studies to adjust for confounding, although they do not provide control for confounders omitted from the propensity score model. We sought to determine if tests used to evaluate logistic model fit and discrimination would be helpful in detecting the omission of an important confounder in the propensity score. Methods Using simulated data, we estimated propensity scores under two scenarios: (1) including all confounders and (2) omitting the binary confounder. We compared the propensity score model fit and discrimination under each scenario, using the Hosmer,Lemeshow goodness-of-fit (GOF) test and the c-statistic. We measured residual confounding in treatment effect estimates adjusted by the propensity score omitting the confounder. Results The GOF statistic and discrimination of propensity score models were the same for models excluding an important predictor of treatment compared to the full propensity score model. The GOF test failed to detect poor model fit for the propensity score model omitting the confounder. C-statistics under both scenarios were similar. Residual confounding was observed from using the propensity score excluding the confounder (range: 1,30%). Conclusions Omission of important confounders from the propensity score leads to residual confounding in estimates of treatment effect. However, tests of GOF and discrimination do not provide information to detect missing confounders in propensity score models. Our findings suggest that it may not be necessary to compute GOF statistics or model discrimination when developing propensity score models. Copyright © 2004 John Wiley & Sons, Ltd. [source]

Ethnic and Racial Disparities in Emergency Department Care for Mild Traumatic Brain Injury

ACADEMIC EMERGENCY MEDICINE, Issue 11 2003
Jeffrey J. Bazarian MD
Abstract Objectives: To identify racial, ethnic, and gender disparities in the emergency department (ED) care for mild traumatic brain injury (mTBI). Methods: A secondary analysis of ED visits in the National Hospital Ambulatory Medical Care Survey for the years 1998 through 2000 was performed. Cases of mTBI were identified using ICD-9 codes 800.0, 800.5, 850.9, 801.5, 803.0, 803.5, 804.0, 804.5, 850.0, 850.1, 850.5, 850.9, 854.0, and 959.01. ED care variables related to imaging, procedures, treatments, and disposition were analyzed along racial, ethnic, and gender categories. The relationship between race, ethnicity, and selected ED care variables was analyzed using multivariate logistic regression with control for associated injuries, geographic region, and insurance type. Results: The incidence of mTBI was highest among men (590/100,000), Native Americans/Alaska Natives (1026.2/100,000), and non-Hispanics (391.1/100,000). After controlling for important confounders, Hispanics were more likely than non-Hispanics to receive a nasogastric tube (OR, 6.36; 95% CI = 1.2 to 33.6); nonwhites were more likely to receive ED care by a resident (OR, 3.09; 95% CI = 1.9 to 5.0) and less likely to be sent back to the referring physician after ED discharge (OR, 0.47; 95% CI = 0.3 to 0.9). Men and women received equivalent ED care. Conclusions: There are significant racial and ethnic but not gender disparities in ED care for mTBI. The causes of these disparities and the relationship between these disparities and post-mTBI outcome need to be examined. [source]