Background: In three randomized trials, medical male circumcision (MMC) reduced HIV acquisition in heterosexual men in sub-Saharan Africa by approximately 60%, after 21–24 months of follow-up. We estimated the 72-month efficacy of MMC against HIV among men retained in the Kisumu randomized trial, in which HIV acquisition was reduced by 60% after 24 months.
Methods: From 2002 to 2005, 2784 men aged 18–24 were enrolled and randomized 1 : 1 to immediate circumcision or control. At trial end in December 2006, control men were offered free circumcision. Follow-up continued to September 2010. Cox proportional hazards regression incorporating stabilized inverse probability of treatment and censoring weights generated through marginal structural modeling, was used to account for potential time-varying confounding and censoring to estimate the efficacy of MMC on HIV risk.
Results: The cumulative 72-month HIV incidence was 7.21% [95% confidence interval (CI): 5.98–8.68%]: 4.81% among circumcised men, 11.0% among uncircumcised men. The crude hazard ratio of HIV seroconversion for circumcised vs. uncircumcised men was 0.38 [95% CI: 0.26–0.55]. In weight-adjusted Cox regression, the hazard ratio was 0.42 [95% CI: 0.26–0.66].
Conclusion: The efficacy of MMC was sustained at 58% at 72 months, similar to overall findings of the three trials under conditions of randomization. These findings provide an estimate of the long-term efficacy of circumcision against HIV acquisition. Our results support programmatic scale-up recommendations that are based on assumptions of sustained efficacy.
aDivision of Epidemiology and Biostatistics, University of Illinois at Chicago School of Public Health, Chicago, Illinois, USA
bDepartments of Medical Microbiology, Community Health Sciences and Medicine, University of Manitoba, Winnipeg, Canada
cImpact Research & Development Organization, Kisumu, Kenya
dDepartment of Medical Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada.
Correspondence to Dr Supriya Mehta, MHS, PhD, 958 SPHPI M/C 923, 1603 West Taylor Street, Chicago, IL 60622, USA. Tel: +1 312 413 7485; fax: +1 312 996 0064; e-mail: firstname.lastname@example.org
Received 17 January, 2013
Revised 11 April, 2013
Accepted 31 May, 2013