Evaluating the impact of male circumcision on HIV risk among men in Zambia: An Inverse Probability of Treatment Weighting for Causal Inference study

Abstract

Abstract BACKGROUND: Zambia rolled out Voluntary Medical Male Circumcision as a strategy for preventing new HIV infections in 2007. However, there is limited data on the intervention's impact. This study estimated the causal impact of male circumcision on the risk of HIV infection among males in Zambia. METHODS: The study applied Inverse Probability of Treatment Weighting on data from the cross-sectional designed 2018 Zambia Demographic and Health Survey, to estimate the causal impact of male circumcision on the risk of HIV infection among circumcised men. RESULTS: Cases of HIV infections were observed in 964 (8.3%) of the total (n = 11611) candidates included in the analysis. The causal impact of male circumcision on the risk of HIV infection among men in Zambia who had undergone the procedure, was a slight reduction of 1.7% (aOR= 0.983; 95% CI= [0.969, 0.997], p= 0.0156). The men exhibited risky sexual behaviour patterns; with only 11.3% (1665/11611) consistently using condoms, 12.7% (1,479/11,611) reporting a sexual debut age over 20 years, and nearly 15% (14.7%; 1712/11611) having two or more sexual partners. Reports of sexually transmitted infections were present, with a higher (p value <0.001) incidence among men who had undergone circumcision compared to those who had not (4.3% [154/3614] vs. 3.5% [279/7997]). CONCLUSION: The causal impact of male circumcision on HIV infections among men in Zambia is low. Risky sexual behaviours were observed, and circumcised men exhibited a higher incidence of sexually transmitted infections compared to their uncircumcised counterparts. This implies the presence of sexual behaviour risk compensation among circumcised men.