Predictors of HIV prevalence among street-based female sex workers in Andhra Pradesh state of India: a district-level analysis

Background: A decline in HIV prevalence among female sex workers (FSWs) has been reported from the Indian state of Andhra Pradesh between the two rounds of integrated biological and behavioural assessment (IBBA) surveys in 2005-06 and 2009, the first of these around the time of start of the Avahan HIV prevention intervention. In order to facilitate further planning of FSW interventions, we report the factors associated with HIV prevalence among street-based FSWs. Methods: Behavioural data from the two rounds of IBBA surveys, district-level FSW HIV prevention program data, and urbanisation data from the Census of India were utilized. A multilevel logistic model was used to investigate factors associated with inter-district variations in HIV positivity among street-based FSWs in the districts by fitting a two-level model. Results: The estimated HIV prevalence among street-based FSWs changed from 16% (95% confidence interval [Cl] 14.2 - 17.7%) to 12.9% (95% Cl 11.5 - 14.2%) from 2005-06 to 2009. HIV positivity was significantly higher in districts with a high proportion of FSWs registered with targeted interventions (odds ratio [OR] 2.02; 95% Cl 1.18-3.45), and in districts with medium (OR 2.54; 95% Cl 1.58-4.08) or high (OR 1.55; 95% Cl 1.05-2.29) proportion of urban population. Districts which had met the condom requirement targets for FSWs had significantly lower HIV positivity (OR 0.50; 95% Cl 0.26-0.97). In round 2 survey, the districts with medium level urbanisation had significantly higher proportion of FSWs registered with HIV intervention programmes and also reported higher consistent condom use with regular partner (p < 0.001). Conclusions: Variations in HIV positivity among street-based FSWs were seen at the district level in relation to HIV intervention programs and the degree of urbanization. These findings could be used to enhance program planning to further reduce HIV transmission in this population.