AEGiS-14IAC: HIV incidence and behavior change in a prospective cohort study of drug users in northern Thailand.

14th International AIDS Conference

Barcelona, Spain - July 7-12, 2002

HIV incidence and behavior change in a prospective cohort study of drug users in northern Thailand.

Int Conf AIDS 2002 Jul 7-12; 14:(abstract no. ThOrC1395)

Celentano DD, Razak MH, Jittiwutikarn J, Srirak N, Vongchak T, Beyrer CC, Rungruenthanakit K, Suriyanon V
Johns Hopkins University, Baltimore, United States

BACKGROUND: Few prospective studies among drug users have been conducted in Thailand. Prospective cohort studies can establish the temporal sequence of risk factors for HIV infection, monitor trends in incidence and assess changing risks among drug users.

METHOD: Since 5/99, HIV negative drug users have been recruited to a 2-year follow-up study at Northern Drug Dependence Treatment Center (NDTC) in Chiang Mai. Interviewers use structured questionnaires, laboratory specimen collection and HIV counseling and testing are conducted at 5 follow-up visits (3, 6, 12, 18, 24 months) to be completed by 12/02. We calculated interim HIV incidence and compared behavior change on follow-up visits with baseline data from first interviews.

RESULTS: From May 1999 to December 2001, 847 completed the baseline incidence visit; 76%, 73%, 67%, and 91% completed their 2nd, 3rd, 4th and 5th follow-up visits, respectively. The majority of those who did not return for follow-up visits were methamphetamine users. During follow-up of 1183.3 person-years, there were 32 seroconverters giving the crude incidence rate (IR) 2.70 per 100 person-years (PY). 31/32 seroconverters were injecting drug users (IDU) and crude IR for IDU is 7.67 per 100PY. Among 342 IDU in the cohort, 4% reported stop using drugs, 59% reported still IDU and 8% switched to non-IDU during the follow-up visits. Among 505 non-IDU, 11% reported stop using drugs and 4% reported switching to IDU. Among those who had sex with CSW, 54% reportedly stopped going to CSW, and 42% stopped having sex during the follow-up visits.

CONCLUSION: HIV incidence among drug users, especially in northern Thailand, remains high. Some risk-reduction was reported (e.g., drug cessation) but more observation is needed before drawing firm conclusions. Seroconversion among IDU emphasizes the point of promoting harm reduction in HIV prevention.

Keywords: AEGIS, Incidence, Cohort Studies, Prospective Studies, HIV Infections, HIV Seropositivity, Thailand, Risk Factors, Acquired Immunodeficiency Syndrome, Follow-Up Studies, Behavior Therapy, epidemiology

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