Characterizing longitudinal health state transitions among heroin, cocaine, and methamphetamine users

Abstract

Aims Characterize longitudinal patterns of drug use careers and identify determinants of drug use frequency across cohorts of primary heroin, methamphetamine (MA) and cocaine users. Design Pooled analysis of prospective cohort studies. Settings Illicit drug users recruited from community, criminal justice and drug treatment settings in California, USA. Participants We used longitudinal data on from five observational cohort studies featuring primary users of heroin (N=629), cocaine (N=694) and methamphetamine (N=474). The mean duration of follow-up was 20.9 years. Measurements Monthly longitudinal data was arranged according to five health states (incarceration, drug treatment, abstinence, non-daily and daily use). We fitted proportional hazards (PH) frailty models to determine independent differences in successive episode durations. We then executed multi-state Markov (MSM) models to estimate probabilities of transitioning between health states, and the determinants of these transitions. Findings Across primary drug use types, PH frailty models demonstrated durations of daily use diminished in successive episodes over time. MSM models revealed primary stimulant users had more erratic longitudinal patterns of drug use, transitioning more rapidly between periods of treatment, abstinence, non-daily and daily use. MA users exhibited relatively longer durations of high-frequency use. Criminal engagement had a destabilizing effect on health state durations across drug types. Longer incarceration histories were associated with delayed transitions towards cessation. Conclusions PH frailty and MSM modeling techniques provided complementary information on longitudinal patterns of drug abuse. This information can inform clinical practice and policy, and otherwise be used in health economic simulation models, designed to inform resource allocation decisions.

Polydrug use and its association with drug treatment outcomes among primary heroin, methamphetamine, and cocaine users

“…I. Hser, Huang, Teruya, & Anglin, 2004), with baseline assessments executed in 1964, 1988–1989, 1995–1997, and 1995 respectively, and the last year of follow-up in 1997, 2002–2003, 1999–2002, and 1996 respectively. All studies recruited subjects from treatment settings only, and baseline drug use profiles across studies were previously presented(Nosyk et al, 2014). …”

Associations of substance use patterns with attempted suicide among persons who inject drugs: Can distinct use patterns play a role?

“…For stimulant users, pharmacological therapies are still under development (Ciccarone, 2011), and the effectiveness of psychosocial interventions is compromised by poor treatment initiation and retention rates (Shearer, 2007). Compared to heroin users, stimulant users are substantially less likely to initiate drug treatment (John et al, 2001) and are more prone to relapse following cessation of drug use (Nosyk et al, 2014), suggesting that health care services may fail to reach and engage stimulant users into care as effectively as opiate users. Innovative care models involving assertive outreach, adapted to the unique profile of stimulant users, may prove useful in reaching this difficult-to-engage sub-group of PWID.…”

Business Cycles and Admissions to Substance Abuse Treatment

“…The appropriate lag structure between admissions to specialty substance abuse treatment and the state unemployment rate in not obvious. Moreover, the lag structure may vary across substances given differences in potential for addiction, harms associated with abuse, types of individuals who abuse substances, capacity constraints of providers who deliver care, and so forth (Dennis et al 2005;Fleury et al 2016;Kessler et al 2001;Lopez-Quintero et al 2011;Nosyk et al 2014). In our main specification, we 4.…”