Factors associated with concurrent heroin use among patients on methadone maintenance treatment in Vietnam: A 24-month retrospective analysis of a nationally representative sample.

backgroundMethadone maintenance treatment (MMT) is highly effective for reducing heroin use and HIV transmission among people who inject opioids. We sought to measure and understand factors associated with continued heroin use, a critical factor affecting treatment outcome among MMT patients in Vietnam.

methodWe collected data from medical charts of a nationally representative sample of patients who were on MMT from May 2008 to December 2013. We selected 10 MMT clinics using probability proportional to size and 50 patients/clinic by systematic random sampling. Concurrent heroin use was defined by self-report/positive urine test recorded in patient charts during month 3, 6, 12, and 24 after MMT initiation. We used multivariable logistic regression to identify factors associated with concurrent heroin use over the first 24 months in treatment.

findingsAll clients used heroin at baseline; concurrent heroin use was 55% at month 3; 19%, 14.6% and 15.2% at month 6, 12, and 24, respectively. Having no family emotional/financial support at baseline versus having this support (AOR = 2.03; 95% confidence interval [CI] = 1.17-3.53); using heroin for <15 years versus ≥15 years at baseline (AOR = 1.55; 95% CI = 1.01-2.38); being HIV-infected/not on antiretroviral treatment (ART; AOR = 1.79; 95% CI = 1.07-2.98) or being HIV infected/on ART (AOR = 2.39; 95% CI = 1.61-3.55), versus not being HIV infected; baseline methamphetamine use versus non-use (AOR = 2.68; 95% CI = 1.08-6.65), were associated with increased odds of concurrent heroin use among patients.

conclusionThe association between concurrent heroin use among MMT patients and lack of family emotional/financial support, highlights the critical importance of these types of support for successful treatment. Association with shorter heroin use history suggests motivational enhancement may reduce concurrent heroin use. Living with HIV, whether on ART or not, is associated with increased concurrent heroin use and suggests safe injection commodities and education, and drug-drug interaction management, are needed for this subgroup. Though few MMT clients reported baseline methamphetamine use, its association with later heroin use suggests the need for effective methamphetamine use interventions.