14th International AIDS Conference Barcelona, Spain - July 7-12, 2002

Int Conf AIDS 2002 Jul 7-12; 14:(abstract no. MoOrC1042)

Murta C, Casado MJ, Casabona J, Ros R, Sierra E, Zaragoza K, Barbera N, Vega de X
CEESCAT, Badalona, Spain

BACKGROUND: The best type of study to identify new HIV infections is the longitudinal cohort study, though it may prove difficult to realise, is expensive and demands a long period of follow-up. Given that many people who look for anonymous HIV testing in Catalonia are repeating it, the aim of this study was to estimate HIV incidence and to characterize factors associated with seroconversion in this population between 1995 and 2000.

METHODS: This study was conducted at six anonymous testing centres of Catalonia, that offer free anonymous and confidential HIV tests and provide counselling. Among repeated testers, people that seroconverted were identified. The time of observation was calculated using the date of the current test and the self-reported date of the previous negative test. Factors independently associated with HIV seroconversion were assessed using the log rank test.

RESULTS: Up to 2000, 2,093 persons repeated anonymous HIV tests. We excluded from analysis persons whose date of previous test was missing (n=182) and whose previous test was positive (n=32) or unknown (n=76). We also excluded persons whose previous test was more than 5 years ago (n=99) or within 2 months (n=27). Of 1,761 subjects those met all inclusion criteria, 55 were seroconverters, with an incidence rate of 2.16 per 100 person-years (PY) (95% CI 1.59 - 2.73). HIV incidence was higher among heterosexual men injecting drug users (IDU) (9.12 per 100 PY) than among heterosexual men non-IDU (0.51 per 100 PY) and homo/bisexual men non-IDU (1.75 per 100 PY). Sexual orientation, IDU, partner with multiple partners and IDU partner were independent predictors for seroconversion.

CONCLUSIONS: Results show that new infections have occurred among repeating HIV testers in Catalonia especially within some groups. While these estimations may present limitations (selection and recall bias), they may be useful for the purposes of planning, implementing and evaluating prevention in these services.

020707
MoOrC1042

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