Background:  Nigeria represents 1 of the top 5 HIV/AIDS epidemics in the world, in terms of the number affected. The number of people requiring ART nationwide is an estimated 0.5 million. Through the PEPFAR program we have scaled-up, managed, and enhanced ART and HIV care efforts in Nigeria. Having stared in 2004, the program now covers ART activities at 29 clinics and a number of satellite centers throughout the country.

Methods:  Eligibility for ART is determined according to Nigerian National ARV Guidelines. Generally, the standard first-line regimen consists of 2 NRTI and 1 NNRTI, typically stavudine (d4T) or zidovudine (AZT), lamivudine (3TC), and nevirapine (NVP) or efavirenz (EFV). Clinical, immunological, and virological profiles are generated at baseline, and months 3, 6, 12, and every 6 months thereafter. The goal of this evaluation was to use non-parametric and logistic regression methods to determine if there were gender differences in virologic outcomes at 12 months.

Results:  As of the August 2008, a total of 46,975 patients have been placed on combination ART (cART) through the Harvard PEPFAR program. At present, 95% of the adult patients are on first-line ARV drugs and 5% are on second-line regimens. Of the patients, 64% on ART are women. In an evaluation of ART outcomes by gender, we found that following 1 year of treatment, more women than men had an undetectable viral load (64% vs 60%; p = 0.001). This difference was not due to numbers of women still present at 1 year as the male:female ratio remained the same as at entry. The differences could also not be attributed to adherence patterns; males and females were equally likely to be ≥95% adherent (69% vs 70%; p = 0.3). At baseline, median CD4 counts were comparable (males 115, females 135) and median viral loads were only slightly lower in women (males 105,220; females 73,863). Median age for women was lower than men (32 vs 39; p = 0.0001). In a multivariate logistic regression model, sex remained the only significant predictor of virologic outcome.

Conclusions:  In an evaluation of data on patients receiving cART in a large treatment program in Nigeria, we found that women had better virologic outcomes at 1-year post-treatment than men. These differences were not due to percentage of patients still receiving treatment at 1 year, differences in drug regimen adherence patterns between men and women, or age. These data indicate that further efforts and evaluations must focus on gender-specific counseling as well as efficacy of treatment.