[A cohort study of HIV incidence among injecting drug users in Dehong Prefecture, Yunnan Province].

Objective To investigate the incidence rates of HIV among injection drug users (IDU) in Dehong Prefecture, Yunnan Province. Methods We recruited 1 413 HIV-negative IDU attending drug rehabilitation centers and identified a further 1 830 potential participants from a historical database from 2004-2009 using the same criteria. Fingerprint recognition technology was used to confirm the identity of all participants. A total of 3 243 HIV-negative IDU were recruited by the end of 2015, of which 2 546 (78.5%) had been followed up at least once since the initial data collection and 697 (21.5%) were lost to follow-up. Epidemiological data were collected through structured face-to-face interviews which included items on knowledge of AIDS, drug use, sexual activity and history of HIV testing. We collected 3-5 ml of venous blood from each subject for HIV testing. The Chi-squared test was used to compare the characteristics of those IDUs successfully followed up and those lost to follow-up. Results We identified 226 new HIV cases among the 2 546 respondents—representing 13 907.1 person-years of follow-up and implying an average HIV incidence rate of 1.6 per 100 person-years over the entire study period (95%CI: 1.4-1.9). The incidence rate (per 100 person-years) was 2.6 (95%CI: 2.2-3.1) for the period 2004-2009 and 1.6 (95%CI: 1.0-2.3), 1.7 (95%CI: 1.1-2.4), 1.2 (95%CI: 0.8-1.9), 0.6 (95%CI: 0.3-1.1), 0.2 (95%CI:0.0-0.7), 0.5 (95%CI: 0.1-1.4) for each year from 2010 to 2015 respectively. Conclusion Although the incidence rate of HIV remains high among IDUs in Dehong, there was a declining trend over the period studied. Key words: Drug users; HIV; Fingerprint identification; Injection drug users; Cohort study