BackgroundIn sub-Saharan Africa, malnutrition is a major complication of HIV disease. Measuring accurately the nutritional benefits of a therapeutic intervention could be an easy-to-monitor secondary outcome.MethodsAnthropometric data were analysed from patients participating in a placebo-controlled trial of co-trimoxazole prophylaxis in adults recruited at early stages of HIV-1 infection in Côte d'Ivoire (COTRIMO-CI ANRS 059 trial). Body mass index (BMI), arm muscle circumference (AMC) and percentage of fat mass (FM) were measured at baseline and quarterly during the follow up. Percentage of variation from the baseline value was compared between treatment groups and within the groups using Studentt-test.ResultsAn improvement of all anthropometric indicators was observed in the first 3 months of follow up in both treatment groups, significant in the co-trimoxazole group (P⩽ 0.0006) but not in the placebo group (P⩾ 0.06). In the co-trimoxazole group, this improvement was maintained for up to 24 months for BMI (P= 0.007), 21 months for AMC (P= 0.02) and only up to 12 months for FM (P= 0.04). The placebo group had a stable anthropometric status up to the end of the trial. Differences between treatment groups were significant for up to 15 months for BMI and AMC and 12 months for FM.ConclusionAs co-trimoxazole prophylaxis is now recommended in Africa as part of a minimum package of care for HIV-infected symptomatic subjects, the short-term improvement of these anthropometric indicators in adults who start co-trimoxazole prophylaxis should be considered as an effective clinical outcome.