O1-S11.02 Determinants of time trends in HIV prevalence in the young antenatal population of Karnataka districts
Authors: Mahajan U , Banandur P , Rajaram S , Duchesne T , Abdous B , Ramesh B M , Moses S , Alary M 
Published: July 2011

BackgroundIn 2003, the Bill & Melinda Gates Foundation initiated a focused HIV prevention program (India AIDS Initiative: Avahan) among high-risk and bridge groups. We studied determinants of time trends in HIV prevalence among young (<25 years) antenatal (ANC) women caused by these intensive prevention intervention (IPI) program compared to non-intensive intervention (Non-IPI) program.MethodsRandom intercept multilevel models were developed using logistic regression (xtmelogit command) to examine effects of IPI, program and district level variables on HIV prevalence among young ANC women. Data from annual sentinel surveillance of ANC women were used as individual level characteristics. Selected program and socio-demographic variables at district level were included as distal variables. Interaction between time and intensity of program intervention was assessed.ResultsHIV prevalence in young ANC women decreased steadily from 1.4% to 0.77% from 2003 to 2007, and increased to 0.83% in 2008 (Adjusted OR (AOR)=0.59, (95% CI):0.45% to 0.77%). Rural (AOR=0.87, 95% CI: 0.76% to 0.99%) and literate women (AOR=0.76,95% CI:0.66% to 0.87%) had lower risk of HIV compared to urban and illiterate women respectively. Presence of major truck halt points (AOR=1.57,95% CI: 1.17% to 2.12%) in the district was associated with high risk of HIV. Higher age at marriage was associated with lower risk of HIV (AOR=0.85,95% CI: 0.78% to 0.93%). There was significant interaction between time and intensity of intervention. In the years 2006 and 2007, Non-IPI districts had a significantly higher risk of HIV compared to IPI districts (AOR2006=1.86, 95% CI: 1.18% to 2.93% and AOR 2007=2.25, 95% CI: 1.39% to 3.62%) respectively. Among the program variables regular contact with high risk group was associated with slightly reduced risk of HIV (AOR=0.998, 95% CI: 0.996% to 0.999%) see Abstract O1-S11.02 table 1.Abstract O1-S11.02 Table 1Determinants of time trends in HIV prevalence in the young antenatal population of Karnataka districtsIndividual/district level characteristicsNull modelRandom intercept model: % high risk group persons contacted regularlyAOR (95% CI)AOR (95% CI)Fixed part of the model Constant0.009 (0.0080 to 0.0114)0.528 (0.097 to 2.8782)Individual characteristicsYear–2003 (Reference)  20040.992 (0.7854 to 1.2521)  20050.804 (0.6287 to 1.0288)  20060.585 (0.4458 to 0.7681)  20070.418 (0.3109 to 0.562)  20080.585 (0.4475 to 0.7649)Locality–Urban (Reference) Rural0.867 (0.7581 to 0.9915)Type of site–District headquarter (Reference) First referral unit–rural0.784 (0.6904 to 0.8907)Literacy–llliterate (reference) Literate0.759 (0.6622 to 0.871)Type of intervention–IPI (reference) Non-IPI0.871 (0.5578 to 1.361)Programme variable % Contacted regularly0.998 (0.9959 to 0.9999)District level variables Mean age at marriage for girls (years)0.848 (0.7773 to 0.9261) Major truck halt points1.573 (1.166 to 2.1212)Interaction Year 2004 and Non-IPI1.101 (0.7184 to 1.6887) Year 2005 and Non-IPI1.443 (0.929 to 2.2427) Year 2006 and Non-IPI1.856 (1.1769 to 2.9253) Year 2007 and Non-IPI2.245 (1.3902 to 3.6249) Year 2008 and Non-IPI1.098 (0.6477 to 1.8601)Random part of the model District-level variance: total0.1333 (0.0642 to 0.2767)0.072 (0.0337 to 0.1530)ConclusionHIV prevalence in ANC population declined significantly in IPI districts from 2003 to 2008 compared to non-IPI districts in Karnataka. IPI had a definite impact on reduction of HIV prevalence in general population during 2006 and 2007. This coincides with the maturity of IPI during 2006 and 2007 along with the initiation of NACP-III in 2007. Learning from IPI might have influenced National AIDS Control Program-III implementation in non-IPI districts in Karnataka leading to similar effects in IPI and non-IPI districts in 2008. Improving female literacy and increasing the age at marriage would help favour reduction of HIV.