Impact of excluded studies on medical male circumcision and HIV risk compensation
Authors: Witness Mapanga, Gwinyai Masukume, Michel Garenne
Journal: The Lancet Global Health (2021)

Yanxiao Gao and colleagues (July, 2021)1Gao Y Yuan T Zhan Y et al.Association between medical male circumcision and HIV risk compensation among heterosexual men: a systematic review and meta-analysis.Lancet Glob Health. 2021; 9: e932-e941Summary Full Text Full Text PDF PubMed Scopus (10) Google Scholar present a systematic review and meta-analysis on the important topic of the association between voluntary medical male circumcision and HIV risk compensation among heterosexual men. Their findings indicate that there were no significant associations between medical male circumcision and multiple sex partners or condomless sex, suggesting that medical male circumcision does not increase higher risk sexual behaviours in heterosexual men. Notably, a study conducted in Zambia2Garenne M Matthews A Voluntary medical male circumcision and HIV in Zambia: expectations and observations.J Biosoc Sci. 2020; 52: 560-572Crossref PubMed Scopus (7) Google Scholar (not included in Gao and colleagues’ systematic review and meta-analysis) considered condom use and the number of sexual partners and reported a tendency towards risk compensation in circumcised men and no reduction in HIV prevalence. For example, circumcised men were reported to have had significantly more extramarital partners (11·1% vs 8·7%; p<0·05) in the 12 months before the Demographic and Health Survey.2Garenne M Matthews A Voluntary medical male circumcision and HIV in Zambia: expectations and observations.J Biosoc Sci. 2020; 52: 560-572Crossref PubMed Scopus (7) Google Scholar We believe such differences, even if small, point towards risk compensation. This study was published before November, 2020, based on nationally representative Demographic and Health Survey data, but was not included in the meta-analysis by Gao and colleagues even though “HIV”, “circumcised”, and “riskier sexual behaviour” are mentioned in the abstract of the study. AMSTAR-2 (a measurement tool to assess systematic reviews), which is an important appraisal tool for systematic reviews that includes randomised or non-randomised studies of health-care interventions, recommends that authors provide a list of excluded studies and justify exclusions.3Shea BJ Reeves BC Wells G et al.AMSTAR 2: a critical appraisal tool for systematic reviews that include randomised or non-randomised studies of healthcare interventions, or both.BMJ. 2017; 358: j4008Crossref PubMed Scopus (2521) Google Scholar Gao and colleagues did not provide such a list; thus, it is not possible to ascertain the impact of exclusions on their study. Given the importance of the topic, providing the list and reasons for the excluded studies would be pertinent. We declare no competing interests. Association between medical male circumcision and HIV risk compensation among heterosexual men: a systematic review and meta-analysisThe promotion of circumcision as an HIV preventive measure does not appear to increase higher-risk sexual behaviours in heterosexual men. Ongoing sexual health education should be maintained as a vital component of effective MMC programmes. Full-Text PDF Open AccessImpact of excluded studies on medical male circumcision and HIV risk compensation – Authors' replyWe thank Witness Mapanga and colleagues for their comment on our meta-analysis.1 The appendix (pp 1–4) shows a list of the excluded studies and reasons they were excluded, based on the exclusion criteria. Full-Text PDF Open Access