UA cloudflare authentication

Browsing by Author "Feaster, Daniel"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Impact of an equality constraint on the class-specific residual variances in regression mixtures: A Monte Carlo simulation study
    (Springer, 2016) Kim, Minjung; Lamont, Andrea E.; Jaki, Thomas; Feaster, Daniel; Howe, George; Van Horn, M. Lee; University of Alabama Tuscaloosa; University of South Carolina Columbia; Lancaster University; University of Miami; George Washington University; University of New Mexico
    Regression mixture models are a novel approach to modeling the heterogeneous effects of predictors on an outcome. In the model-building process, often residual variances are disregarded and simplifying assumptions are made without thorough examination of the consequences. In this simulation study, we investigated the impact of an equality constraint on the residual variances across latent classes. We examined the consequences of constraining the residual variances on class enumeration (finding the true number of latent classes) and on the parameter estimates, under a number of different simulation conditions meant to reflect the types of heterogeneity likely to exist in applied analyses. The results showed that bias in class enumeration increased as the difference in residual variances between the classes increased. Also, an inappropriate equality constraint on the residual variances greatly impacted on the estimated class sizes and showed the potential to greatly affect the parameter estimates in each class. These results suggest that it is important to make assumptions about residual variances with care and to carefully report what assumptions are made.
  • Thumbnail Image
    Item
    Racial discrimination in medical care settings and opioid pain reliever misuse in a US cohort: 1992 to 2015
    (PLOS, 2019) Swift, Samuel L.; Glymour, M. Maria; Elfassy, Tali; Lewis, Cora; Kiefe, Catarina I.; Sidney, Stephen; Calonico, Sebastian; Feaster, Daniel; Bailey, Zinzi; Al Hazzouri, Adina Zeki; University of New Mexico; University of California San Francisco; University of Miami; University of Alabama Tuscaloosa; University of Massachusetts Boston; Kaiser Permanente; Columbia University
    Background In the United States whites are more likely to misuse opioid pain relievers (OPRs) than blacks, and blacks are less likely to be prescribed OPRs than whites. Our objective is to determine whether racial discrimination in medical settings is protective for blacks against OPR misuse, thus mediating the black-white disparities in OPR misuse. Methods We used data from 3528 black and white adults in the Coronary Artery Risk Development in Young Adults (CARDIA) study, an ongoing multi-site cohort. We employ causal mediation methods, with race (black vs white) as the exposure, lifetime discrimination in medical settings prior to year 2000 as the mediator, and OPR misuse after 2000 as the outcome. Results We found black participants were more likely to report discrimination in a medical setting (20.3% vs 0.9%) and less likely to report OPR misuse (5.8% vs 8.0%, OR = 0.71, 95% CI = 0.55, 0.93, adjusted for covariates). Our mediation models suggest that when everyone is not discriminated against, the disparity is wider with black persons having even lower odds of reporting OPR misuse (OR = 0.63, 95% CI = 0.45, 0.89) compared to their white counterparts, suggesting racial discrimination in medical settings is a risk factor for OPR misuse rather than protective. Conclusions These results suggest that racial discrimination in a medical setting is a risk factor for OPR misuse rather than being protective, and thus could not explain the seen black-white disparity in OPR misuse.