Epidemiology of HIV-1 infection in opiate users in Northern Thailand

Abstract

Characterizing the epidemiology of HIV-1 infection in Northern Thai opiate users is important in developing control strategies in this ethnically diverse and culturally distinct region. A cross-sectional survey of drug users first admitted between 1993 and 1995 at the Northern Drug Dependence Treatment Center, Mae Rim, Thailand, was conducted. Patients (n = 4197) were interviewed at intake about their history of drug use when they provided serum specimens for HIV-1 antibody testing. The HIV-1 prevalence was 18.6%, with men having a fourfold higher prevalence than women. Wide diversity in HIV-1 prevalence was seen by ethnicity; the HIV-1 prevalence among Thai lowlanders was four times greater than that among ethnic minorities (hill tribes). Differences in HIV-1 prevalence were the result of differences in opiate use; hill tribes frequently smoked or ingested opium, whereas Thai lowlanders injected heroin. The high HIV-1 prevalence suggests that preventive interventions for risk reduction are urgently needed in these populations. Education about the risks of injection drug use (IDU) as well as information concerning needle disinfection and expansion of drug treatment are required to reduce the risk of HIV-1 transmission associated with sharing injection equipment. Further, increasing sources of sterile needles should be considered for active users, especially for those in more remote settings.

PIP: A cross-sectional survey of 4197 men and women admitted to the Northern Drug Dependence Treatment Center in Mae Rim, Thailand, in 1993-95 was conducted to characterize the epidemiology of HIV-1 infection in Northern Thai opiate users. Overall HIV prevalence was 18.6%, with men having a more than 4-fold higher prevalence than women (20.0% and 5.9%, respectively). HIV prevalence was also 4 times greater among Thai lowlanders (29.4%) than hill tribes (9.1%). Interviews revealed that, while lowlanders were most likely to inject heroin, hill tribes more frequently smoked or ingested opium. Overall, heroin users were nine times more likely to be HIV-infected than those who used opium (36.3% and 4.0%, respectively). These findings suggest that cultural differences in patterns of drug use produce different HIV prevalences among ethnic groups in Northern Thailand. Multivariate regression analysis of HIV risk factors, after adjustment for drug of choice and route of administration, found significantly reduced risks for married and cohabitating persons, civil servants, and students and significantly elevated risks for those with only a primary education or employed in agriculture or business. Education about the risks of injection drug use, as well as information on needle disinfection and expanded sources for sterile needles, is needed, especially in Thailand's more remote settings.