Daniel Feaster | University of Miami School of Medicine (original) (raw)

Papers by Daniel Feaster

Open Forum Infectious Diseases, 2021

Background Direct-acting antivirals can cure hepatitis C virus (HCV). Persons with HCV/HIV and li... more Background Direct-acting antivirals can cure hepatitis C virus (HCV). Persons with HCV/HIV and living with substance use are disadvantaged in benefiting from advances in HCV treatment. Methods In this randomized controlled trial, participants with HCV/HIV were randomized between February 2016 and January 2017 to either care facilitation or control. Twelve-month follow-up assessments were completed in January 2018. Care facilitation group participants received motivation and strengths-based case management addressing retrieval of HCV viral load results, engagement in HCV/HIV care, and medication adherence. Control group participants received referral to HCV evaluation and an offer of assistance in making care appointments. Primary outcome was number of steps achieved along a series of 8 clinical steps (eg, receiving HCV results, initiating treatment, sustained virologic response [SVR]) of the HCV/HIV care continuum over 12 months postrandomization. Results Three hundred eighty-one in...

Behavior Research Methods, 2019

Regression mixture models are one increasingly utilized approach for developing theories about an... more Regression mixture models are one increasingly utilized approach for developing theories about and exploring the heterogeneity of effects. In this study we aimed to extend the current use of regression mixtures to a repeated regression mixture method when repeated measures, such as diary-type and experience-sampling method, data are available. We hypothesized that additional information borrowed from the repeated measures would improve the model performance, in terms of class enumeration and accuracy of the parameter estimates. We specifically compared three types of model specifications in regression mixtures: (a) traditional single-outcome model; (b) repeated measures models with three, five, and seven measures; and (c) a single-outcome model with the average of seven repeated measures. The results showed that the repeated measures regression mixture models substantially outperformed the traditional and average single-outcome models in class enumeration, with less bias in the parameter estimates. For sample size, whereas prior recommendations have suggested that regression mixtures require samples of well over 1,000 participants, even for classes at a large distance from each other (classes with regression weights of .20 vs. .70), the present repeated measures regression mixture models allow for samples as low as 200 participants with an increased number (i.e., seven) of repeated measures. We also demonstrate an application of the proposed repeated measures approach using data from the Sleep Research Project. Implications and limitations of the study are discussed.

Educational and Psychological Measurement, 2018

Regression mixture models are a statistical approach used for estimating heterogeneity in effects... more Regression mixture models are a statistical approach used for estimating heterogeneity in effects. This study investigates the impact of sample size on regression mixture’s ability to produce “stable” results. Monte Carlo simulations and analysis of resamples from an application data set were used to illustrate the types of problems that may occur with small samples in real data sets. The results suggest that (a) when class separation is low, very large sample sizes may be needed to obtain stable results; (b) it may often be necessary to consider a preponderance of evidence in latent class enumeration; (c) regression mixtures with ordinal outcomes result in even more instability; and (d) with small samples, it is possible to obtain spurious results without any clear indication of there being a problem.

Alcohol and alcoholism (Oxford, Oxfordshire), Jan 27, 2018

We aimed to identify psychosocial factors related to problem drinking among patients with poorly ... more We aimed to identify psychosocial factors related to problem drinking among patients with poorly controlled human immunodeficiency virus (HIV) infection. We aimed to identify psychosocial factors related to problem drinking among those with poorly controlled HIV infection. Increased levels of interpersonal conflict were associated with greater severity of alcohol problems. Poorer mental health, medical mistrust and less satisfaction with one's physician related to excessive drinking. This secondary analysis used baseline data from a large multisite randomized controlled trial of substance users whose HIV infection was currently poorly controlled, from 11 urban hospitals across the USA. Participants were HIV-infected adult inpatients (n = 801; 67% male, 75% African American) with substance use histories. Participants self-reported on their drinking, perceived health, mental health, social relationships and patient-provider relationship. Structural equation models examined psychos...

Drug and Alcohol Dependence, 2016

Objectives-Sexually transmitted infections (STIs) are significant public health and financial bur... more Objectives-Sexually transmitted infections (STIs) are significant public health and financial burdens in the United States. This manuscript examines the relationship between substance use and prevalent and incident STIs in HIV-negative adult patients at STI clinics. Methods-A secondary analysis of Project AWARE was performed based on 5,012 patients from 9 STI clinics. STIs were assessed by laboratory assay and substance use by self-report. Patterns of substance use were assessed using latent class analysis. The relationship of latent class to STI rates was investigated using Poisson regression by population groups at high risk for STIs defined by participant's and partner's gender Results-Drug use patterns differed by risk group and substance use was related to STI rates with the relationships varying by risk behavior group. Substance use treatment participation was associated with increased STI rates Conclusions-Substance use focused interventions may be useful in STI clinics to reduce morbidity associated with substance use. Conversely, gender-specific sexual health interventions may be useful in substance use treatment.

JAMA internal medicine, Jan 16, 2015

Several randomized clinical trials have demonstrated the efficacy of preexposure prophylaxis (PrE... more Several randomized clinical trials have demonstrated the efficacy of preexposure prophylaxis (PrEP) in preventing human immunodeficiency virus (HIV) acquisition. Little is known about adherence to the regimen, sexual practices, and overall effectiveness when PrEP is implemented in clinics that treat sexually transmitted infections (STIs) and community-based clinics serving men who have sex with men (MSM). To assess PrEP adherence, sexual behaviors, and the incidence of STIs and HIV infection in a cohort of MSM and transgender women initiating PrEP in the United States. Demonstration project conducted from October 1, 2012, through February 10, 2015 (last date of follow-up), among 557 MSM and transgender women in 2 STI clinics in San Francisco, California, and Miami, Florida, and a community health center in Washington, DC. Data were analyzed from December 18, 2014, through August 8, 2015. A combination of daily, oral tenofovir disoproxil fumarate and emtricitabine was provided free o...

Structural Equation Modeling: A Multidisciplinary Journal, 2015

This paper proposes a novel exploratory approach for assessing how the effects of level-2 predict... more This paper proposes a novel exploratory approach for assessing how the effects of level-2 predictors differ across level-1 units. Multilevel regression mixture models are used to identify latent classes at level-1 that differ in the effect of one or more level-2 predictors. Monte Carlo simulations are used to demonstrate the approach with different sample sizes and to demonstrate the consequences of constraining 1 of the random effects to zero. An application of the method to evaluate heterogeneity in the effects of classroom practices on students is used to show the types of research questions which can be answered with this method and the issues faced when estimating multilevel regression mixtures. A common research objective is to assess heterogeneity in the effects of a predictor on an outcome. Take, for example, a study looking at the effects of teaching style on student achievement that finds no average effects on student outcomes. A logical next question is to examine whether the effects of teaching differs across students (Van Horn & Ramey, 2003). The standard approach would be to test cross-level interactions between student-level predictors and the classroom-level variable teaching style. This yields an understanding of the impact of specified variables on specific students. However, this is not the same thing as a global assessment of heterogeneity in the effects of teaching style. An alternative approach would be to use a regression mixture (also known as mixture regression or latent class regression) model to explore for latent classes of students who respond differently to

JAIDS Journal of Acquired Immune Deficiency Syndromes, 2015

Introduction-Pre-exposure prophylaxis (PrEP) is a promising approach to reducing HIV incidence. T... more Introduction-Pre-exposure prophylaxis (PrEP) is a promising approach to reducing HIV incidence. Thus garnering the support of HIV providers, who are most familiar with antiretrovirals and likely to encounter patients in HIV serodiscordant relationships, to scale-up PrEP implementation is essential. We sought to determine whether certain subgroups of HIV providers were more likely to intend to prescribe PrEP. Methods-Surveys were administered to HIV providers in Miami, Florida and Washington, DC. Composite scores were developed to measure PrEP knowledge, experience, and likelihood of prescribing. Latent class analysis (LCA) was used to stratify provider attitudes toward PrEP. Results-Among 142 HIV providers, 73.2% had cared for more than 20 HIV-infected patients in the prior 3 months; 17% had ever prescribed PrEP. LCA identified two classes of providers (entropy 0.904); Class 1 (n=95) found PrEP less effective and perceived barriers to prescribing it; Class 2 (n=47) perceived PrEP as moderately effective and perceived fewer barriers to prescribing it. Compared to Class 2, Class 1 had significantly less experience with PrEP delivery (t(22.7)=2.88, p=0.009

Behavior research methods, Jun 3, 2015

Regression mixture models are a novel approach to modeling the heterogeneous effects of predictor... more 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 paramet...

Journal of Community Health, 2015

The aim is to study the trends of cigarette smoking from 2001 to 2012 using a California represen... more The aim is to study the trends of cigarette smoking from 2001 to 2012 using a California representative sample in the US. Data was taken from the California Health Interview Survey (CHIS) from 2001 to 2012, which is a population-based, biennial, random digit-dial telephone survey of the non-institutionalized population. The CHIS is the largest telephone survey in California and the largest state health survey in the US. 282,931 adults (n = 184,454 with age 18-60 and n = 98,477 with age [60) were included in the analysis. Data were weighted to be representative and adjusted for potential covariance and nonresponse biases. During 2001-2012, the prevalence of current smoking decreased from 18.86 to 15.4 % among adults age 18-60 (b =-0.8, p = 0.0041). As for adults age [60, the prevalence of current smoking trend decreased with variations, started from 9.66 % in 2001, slightly increased to 9.74 % in 2003, but then gradually decreased, falling to 8.18 % in 2012. In 2012, there was a 14 % reduction of daily smoking adults age 18-60 (OR 0.84, 95 % CI 0.76-0.93, p = 0.0006) compared to 2001, while no significant reduction of daily smoking was observed for those age [60. The reductions of smoking prevalence for adults younger than 60 are encouraging. However, there is a concern for smoking cessation rates among those older than 60 years of age, particularly for African Americans.

AIDS and behavior, Jan 8, 2015

Substance users are at increased risk for HIV and HCV infection. Still, many substance use treatm... more Substance users are at increased risk for HIV and HCV infection. Still, many substance use treatment programs (SUTP) fail to offer HIV/HCV testing. The present secondary analysis of screening data from a multi-site randomized trial of rapid HIV testing examines self-reported HIV/HCV testing patterns and serostatus of 2473 SUTP patients in 12 community-based sites that had not previously offered on-site testing. Results indicate that most respondents screened for the randomized trial tested more than a year prior to intake for HIV (52 %) and HCV (38 %). Prevalence rates were 3.6 and 30 % for HIV and HCV, respectively. The majority of participants that were HIV (52.2 %) and HCV-positive (40.5 %) reported having been diagnosed within the last 1-5 years. Multivariable logistic regression showed that members of high-risk groups were more likely to have tested. Bundled HIV/HCV testing and linkage to care issues are recommended for expanding testing in community-based SUTP settings.

Purpose: Many US sexually transmitted disease (STD) clinics conduct routine enzyme immunoassay (E... more Purpose: Many US sexually transmitted disease (STD) clinics conduct routine enzyme immunoassay (EIA) laboratory HIV testing that requires follow up to receive results. On-site rapid HIV testing delivers results in 20 minutes at a higher initial cost, but reduces follow up costs and risks of loss to follow up for newly identified HIV cases. Methods: Using micro-costing techniques, we determined the average cost per person offered a rapid HIV test for two strategies: 1) rapid test with information only and 2) rapid test with risk-reduction counseling. Data were from seven public health STD clinics participating in a randomized trial comparing the effectiveness and cost-effectiveness of the two strategies. Data included staff activity logs, clinic overhead including additional space for on-site rapid testing, and supplies. We applied national labor rates and supply costs. Analysis was from the STD clinic perspective; start-up costs and patient costs were excluded. We calculated the thr...

Educational and Psychological Measurement, 2014

Research increasingly emphasizes understanding differential effects. This article focuses on unde... more Research increasingly emphasizes understanding differential effects. This article focuses on understanding regression mixture models, which are relatively new statistical methods for assessing differential effects by comparing results to using an interactive term in linear regression. The research questions which each model answers, their formulation, and their assumptions are compared using Monte Carlo simulations and real data analysis. The capabilities of regression mixture models are described and specific issues to be addressed when conducting regression mixtures are proposed. The article aims to clarify the role that regression mixtures can take in the estimation of differential effects and increase awareness of the benefits and potential pitfalls of this approach. Regression mixture models are shown to be a potentially effective exploratory method for finding differential effects when these effects can be defined by a small number of classes of respondents who share a typical...

Background: Alcohol/drug use during or before sex potentially increases HIV transmission risk. Ob... more Background: Alcohol/drug use during or before sex potentially increases HIV transmission risk. Objectives: 1) Describe the prevalence of severe drug use and risky sexual behaviors among clients in substance use disorder treatment programs. 2) Examine the associations between severe drug use and risky sexual behaviors among clients having unprotected sex within two hours of using drugs or alcohol. Methods: A total of 1281 participants from 12 US community-based substance use disorder treatment programs were included in this study. Chi-square tests, univariate, multiple logistic models were used in this planned secondary analysis of data from CTN-0032, a trial conducted within the National Drug Abuse Treatment Clinical Trials Network. Results: People using pain medication (OR=3.42, 95% CI=1.76-6.66, p=0.0003), marijuana (OR=1.72, 95% CI=1.08-2.72, p=0.0219), or methamphetamines (OR=5.98, 95% CI=1.16-30.87, p=0.0327) were more likely to report unprotected sex within two hours of using ...

Background: Substance use is associated with heightened prevalence of sexual risk behaviors, incr... more Background: Substance use is associated with heightened prevalence of sexual risk behaviors, increasing the likelihood of HIV transmission. Objective: We examined the relationship between substance use and sexual risk behaviors among 1281 participants from 12 US community-based substance use disorder treatment programs. Methods: Chi-square tests, univariate, and multiple logistic models were used in this planned secondary analysis of data from CTN-0032, a trial conducted within the National Drug Abuse Treatment Clinical Trials Network. Results: Cocaine (OR=2.31, 95%CI= 1.79-2.97, p<0.0001) and Viagra (OR=3.04, 95%CI= 1.30-7.13, p=0.0106) use were associated with more than twice the likelihood of engaging in sexual risk behaviors including multiple sex partners, unprotected anal sex, unprotected sex with non-primary partners, and unprotected sex with partners of unknown HIV serostatus. In addition, weekly use of tranquilizers/barbiturates (OR=1.58, 95%CI= 1.05-2.36, p=0.027), crac...

Background: HIV testing is a powerful transmission reduction strategy. Yet, significant numbers o... more Background: HIV testing is a powerful transmission reduction strategy. Yet, significant numbers of substance users are not routinely tested, despite their high risk status. Objective: We examined changes in readiness for HIV testing in a randomized trial of HIV testing strategies. Methods: A total of 1281 participants from 12 US community-based substance use disorder treatment programs were included in this planned secondary analysis of data from CTN-0032, a trial conducted within the National Drug Abuse Treatment Clinical Trials Network. There were three study arms: (1) referral for off-site HIV testing, (2) HIV risk-reduction counseling with on-site rapid HIV testing, and (3) verbal information about testing with on-site rapid HIV testing. Results: Participants in both on site testing arms reported significantly higher readiness for HIV testing (30.3% vs 56.3% vs 54.8%), higher HIV test completion (47.6% vs 88.9% vs 89.6%) and a higher proportion of receiving HIV test results (90....

Addiction, 2014

Aims-To evaluate the cost-effectiveness of rapid hepatitis C virus (HCV) and simultaneous HCV/HIV... more Aims-To evaluate the cost-effectiveness of rapid hepatitis C virus (HCV) and simultaneous HCV/HIV antibody testing in substance abuse treatment programs. Design-We used a decision analytic model to compare the cost-effectiveness of no HCV testing referral or offer, off-site HCV testing referral, on-site rapid HCV testing offer, and on-site rapid HCV and HIV testing offer. Base case inputs included 11% undetected chronic HCV, 0.4%

Sexually Transmitted Diseases, 2014

Introduction-Rapid HIV testing in high-risk populations can increase the number of persons who le... more Introduction-Rapid HIV testing in high-risk populations can increase the number of persons who learn their HIV status and avoid spending clinic resources to locate persons identified as HIV-infected. Methods-We determined the cost to sexually transmitted disease clinics of point-of-care rapid HIV testing using data from 7 public clinics that participated in a randomized trial of rapid testing with and without brief patient-centered risk-reduction counseling in 2010. Costs included counselor and trainer time, supplies, and clinic overhead. We applied national labor rates and test costs. We calculated median clinic start-up costs and mean cost per patient tested, and projected §

PsycEXTRA Dataset

This study examined the relation of race/ethnic-matching (i.e., matching therapist and client bas... more This study examined the relation of race/ethnic-matching (i.e., matching therapist and client based on self-reported race/ethnicity [REM]) to the treatment outcomes of 471 Hispanic, African American, and White adolescents in substance abuse treatment. Additionally, exploratory analyses were conducted to examine family functioning as a moderator variable between racial/ethnic match and treatment outcomes. Logistic and multiple regression analyses revealed that REM, alone, did not significantly predict the treatment outcomes of the African American and White adolescents. However, REM predicted an increase in the externalizing behaviors (e.g., non-compliance, aggression, hyperactivity) and substance use of Hispanic adolescents 12 months post baseline assessment. Family functioning moderated the relationship between REM and treatment engagement for African American adolescents. As family functioning worsened, African American adolescents who were matched had a higher likelihood of treatment engagement. Implications for substance abuse treatment with ethnic minority adolescents and future race/ethnic-matching research are provided. Sorie, know that God has blessed me with you and I thank you for your support, encouragement, and proof reading. La'Trice, you have been one of my best supporters since I started in the program and I thank you for your friendship and mentorship. Drs. Mike Robbins, Dan Feaster, and Natali Teszler, I thank you for your invaluable input and assistance during this project. Last, but not least, I acknowledge my thesis committee members (Drs. Burlew [chair], Jacquez, and Peteet) for their support and investment of time into this project. In the words of Pearl S. Buck, "The person who tries to live alone will not succeed as a human being. His heart withers if it does not answer another heart. His mind shrinks away if he hears only the echoes of his own thoughts and finds no other inspiration." Those I have acknowledged have truly been my inspiration to grow and succeed beyond my current abilities and inadequacies. Thank you for assisting me in the completion of this project. v

Multivariate Behavioral Research, 2013

Regression mixture models have been increasingly applied in the social and behavioral sciences as... more Regression mixture models have been increasingly applied in the social and behavioral sciences as a method for identifying differential effects of predictors on outcomes. While the typical specification of this approach is sensitive to violations of distributional assumptions, alternative methods for capturing the number of differential effects have been shown to be robust. Yet, there is still a need to better describe differential effects that exist when using regression mixture models. The current study tests a new approach that uses sets of classes (called differential effects sets) to simultaneously model differential effects and account for non-normal error distributions. Monte Carlo simulations are used to examine the performance of the approach. The number of classes needed to represent departures from normality is shown to be dependent on the degree of skew. The use of differential effects sets reduced bias in parameter estimates. Applied analyses demonstrated the implementation of the approach for describing differential effects of parental health problems on adolescent body mass index using differential effects sets approach. Findings support the usefulness of the approach which overcomes the limitations of previous approaches for handling non-normal errors.