Longitudinal patterns of substance abuse in the Veterans Aging Cohort Study (VACS) Traci Craig Green Yale School of Public Health Yale Center for Interdisciplinary Research on AIDS Kirschstein Pre-doctoral National Research Service Training Fellowship, NIDA (5F31DA023862) VACS Investigators Meeting 14 October, 2008 Longitudinal patterns of substance abuse in the Veterans Aging Cohort Study (VACS)

Substance Abuse, Aging, & HIV Prevalence of drug abuse increasing in older age groups Natural history of substance use/abuse suggests Chronicity, little initiation >age 30, reduction of use w/time Little known about patterns of substance use/abuse over course of disease Alcohol use can affect adherence, HIV progression, death Inconsistent associations between drug use & HIV progression, death py illicit drug use increased between 2002 and 2005 among people 50-59. Aging of baby boomer generation—which has the highest rates of substance abuse vs. previous generations Everyone knows that People living longer with HIV

A Latent Variable Framework Latent variables Cannot be directly observed Inferred from other, directly observable & measurable variables Example: happiness Assumptions Individuals can be divided into meaningful subgroups (latent classes: c1-c5), based on similarities in responses Classes are mutually exclusive & exhaustive Empirical method of classification Figure serves as illustration of LCA approach where c1-c5 represent subpopulations of the total population of “drug users” which we otherwise cannot directly observe. Instead, we ‘detect’ these subpopulations by analyzing indicators of their presence—here, self-reported use/non use of drugs.

Conceptualizing latent trajectories GMM=Growth Mixture Model HLM=Hierarchical Linear Model LCGA=Latent Class Growth Analysis

N=6351

Class Putative class description Similarities with other classes Uniqueness of class HIV-specific differences 1 Nonusers Fewer minorities like class 2,5 Injection history, lifestyle instability low like class 2 High medical problems, obesity like class 3 Older age, more gender diversity Low psychiatric diseases, high quality of life/mental scores, low alcohol use & problem drinking Higher quality of life physical scores for HIV+ Fewer comorbidities for HIV+, lowest rate of AIDS associated illness 2 Past primarily marijuana Like class 1 in most socio-demographics, lifestyle stability, quality of life Lowest medical disease More history of smoking, past year drinking than class 1 HIV+ similar to HIV+ class 5: fewer non-white, employment, lifestyle stability but less past year drinking, better quality of life mental health AIDS-associated illness similar to 3,5 3 Past multidrug Racial/ethnic background, employment status, obesity like class 1 Smoking prevalence like class 4, 5 Problematic scores among drinkers like class 4, 5 Oldest of drug using classes (2-5) Highest HCV prevalence, medical problems, former IVD Lowest past year drinking prevalence Current lifestyle stability HCV coinfection highest HIV+ more likely to smoke HIV+ formerly injected heroin and cocaine; HIV- less often injected any drug AIDS-associated illness similar to class 2, 5 4 High consequence, multidrug HCV positivity, history of smoking & IVD like class 3 HIV- like class 5 HIV- Primarily males aged 41-50, African American, unmarried/ not living with partner, lowest income, employment & education status, greatest lifestyle instability Many currently smoking & injecting drugs, recent & heavy drinking Highest psychiatric disease; receiving treatment (SA,MH) More injection of drugs, cigarette smoking among HIV+ vs. HIV- Less problematic drug use among HIV+ vs. HIV- HIV+ receiving proportionately less treatment (SA, MH) High prevalence of AIDS-associated illness 5 Low consequence, primarily marijuana HIV+ like classes 1, 2 -socio-demographics, highly stable, lower problem drinking (class 2) -lower medical & psychiatric disease HIV- like classes 3, 4 -drink as heavily & often (class 4), currently smoke -history of lifestyle instability (class 3) Low HCV prevalence History of but no current IVD SA treatment rare MH scores low but treatment not common Least likely of HIV+ classes to be obese; lowest prevalence of diabetes, hypertension Youngest HIV+ class, highest education level, lowest minority membership AIDS-associated illness lower than other users (class 4)

Study Aims To determine the prevalence & correlates of substance abuse trajectories among an older adult population with & without HIV Hypotheses: >3 trajectories of substance abuse HIV status will differentiate trajectories Age, race, medical & psychiatric disease, & treatment status will contribute to definition of trajectories

Analysis Indicators of self reported substance use VACS8, 2+ survey responses N=4920 Demographically & clinically similar to full sample Indicators of self reported substance use AUDIT-C score & frequency of use of heroin, cocaine/stimulants, marijuana Baseline, Follow ups 1,2,3 Single & Joint substance LCGA & GGMMs, quadratic change, class sizes 1-9 Correlates Socio-demographics (age, race, education, income) Medical & psychiatric comorbidities baseline diagnosis Substance abuse, mental health treatment past year

HIV- HIV+ 8 trajectory classes for HIV+ and 8 for HIV-. HIV differentiates class prevalence (how tall the colored stacks are) and the actual class composition (color of stacks). HIV- HIV+

trajectories do overlap but also several unique patterns Alcohol trajectories do overlap but also several unique patterns slopes for many substances close to 0, suggesting not much change in drug use over 4 years' time No positve slopes! That is, no new drug use initiation at this point LCA classes are repeated, but splinter when slopes become relevant: marijuana use class, current multidrug users class Similarities reducers, non users, past multidrug users, and current multidrug users recreational drug use (cocaine, marijuana) Differences HIV- had more change, HIV+ had more stability in substance use classes (14 vs. 8 sig slopes/quad parameters) HIV+ exhibited fewer problem drinking patterns (1.6% vs. 6.1% HIV-) HIV- unique class: high AUDITC with past primarily marijuana use HIV+ unique classes: marijuana use (daily) with past hx of other drugs & heavy marijuana use with no hx of other drugs recreational drug use class among HIV- has more problem drinking

HIV+ reducers—increase SA and MH tx over time—highest use and greater mh need/dx vs. multidrug users whose tx hx is erratic HIV- reducers—increase SA (2nd highest) and MH (1st highest) tx over time; multidrug users MH tx is very erratic despite similar psychiatric disease dx rates Not correlated: Hispanic/other ethnicity, death, CD4, AIDS-associated illness (bl, f/u 4)

Limitations Sample generalizability Did not measure abuse of prescription drugs, benzodiazepines, club drugs Unmeasured covariates: motivations for use, expectancies, readiness to quit

Conclusions Multiple trajectories of substance use exist, HIV status differentiates several distinct patterns Trajectories indicate current drug use is prevalent even with older age, despite illness: 21.9% HIV-, 36.8% HIV+ Interventions needed to increase adherence, age-appropriate treatment Results can help suggest ways to better target efforts -not a simple dichotomy -NSDUH 2005: 14.4% of adults have used an illicit drug in the past year

Thank you! Special thanks to the VACS writing committee: Kendall Bryant, Nancy Day, David Fiellin, Adam Gordon, Joe Goulet, Robert Heimer, Amy Justice, Trace Kershaw, Kevin Kraemer, Haiqun Lin, Steve Maisto traci.c.green@yale.edu