The figure shows the trial profile. No clusters were lost to follow-up. Twelve month follow-up rates for women with known HIV status at baseline were 75.8% and 75.3% in the intervention and control arms and 75.1% and 71.8% for men in the intervention and control arms, respectively. At 24 months, 73.1% (intervention) and 76.0% (control) of women with baseline HIV results were retested and 69.5% (intervention) and 69.2% (control) of men were tested again for HIV. Loss to follow-up was mainly because participants had moved and could not be located. At baseline, 9.8% of men and 6.3% of women had a main partner also in the study.
Eighteen participants died during the main study and one committed suicide in the pilot study (figure). Causes of death in the main study were interpersonal violence (six), suicide (three), injuries from traffic incidents (two), and a range of natural causes (seven), including AIDS (one). Four of the non-natural deaths were in the control arm and seven in the intervention arm. All deaths were investigated and none was linked to activities of the study. There were no other serious adverse events.
From the available attendance registers (an incomplete set), 90 (16.8%) men and 63 (12.5%) women did not participate in any of the Stepping Stones sessions, and 189 (31.7%) men and 228 (35.7%) women did not attend the short intervention. Some 324 (60.7%) men and 298 (59.1%) women attended 75% or more of the Stepping Stones sessions, and 147 (27.5%) men and 128 (25.4%) women attended the complete programme.
Table 2 shows the participants’ baseline characteristics. The two arms were similar for both sexes, although participants in the control arm were slightly more educated (P=0.09 for women, P=0.08 for men).
Table 2 Social and demographic characteristics of two study arms. Figures are numbers (percentages)
Table 3 shows the results for the comparison of incidence rates of HIV and HSV-2 between the two study arms. After adjustment for stratum, baseline HIV prevalence in the cluster, and age of the respondent, Stepping Stones had little effect on the incidence of HIV. The incidence of HSV-2 was significantly lower in the Stepping Stones arm than the control arm (incidence rate ratio 0.67, 95% confidence interval 0.46 to 0.97, P=0.036). This represents a 33% reduction in incidence and translates to 34.9 (1.6 to 68.2) infections being prevented over a two year period per 1000 people in the programme. There was no evidence of heterogeneity—that is, the effect of Stepping Stones on incidence of HSV-2 was similar for men and women.
Table 3 Incidence of HIV and HSV-2 according to intervention
Table 4 shows the results of the analysis of the other outcomes for women. There was no evidence of difference in the expected direction between the two arms in any of these outcomes. At 12 months the proportion of women who had transactional sex with a casual partner since the first interview was higher in the Stepping Stones arm. It is worth noting, however, that there was little difference between the two arms in the proportions of women who had a casual partner and that the difference in the proportions having transactional sex with a casual partner had disappeared by month 24. There was slight evidence (P=0.11) that the incidence of pregnancy was higher in the Stepping Stones arm at 24 months.
Table 4 Other outcomes at 12 and 24 months in women according to intervention
Some of the other outcomes for men did show differences in the hypothesised direction (table 5). A significantly lower proportion of men in the intervention arm reported having had transactional sex with a casual partner at 12 months, although this difference had disappeared by 24 months. The proportion of men who perpetrated physical or sexual intimate partner violence was significantly lower in the Stepping Stones arm at 24 months, and there was some evidence that it was also lower at 12 months. There was some evidence that a lower proportion of men in the Stepping Stones reported raping or attempting rape at 12 months and that a lower proportion had any casual partner at 12 months. A significantly lower proportion of men in the Stepping Stones arm reported problem drinking at 12 months, and there was some evidence that a lower proportion were depressed at 24 months and that a lower proportion initiated drug misuse between 12 and 24 months.
Table 5 Results for men: other outcomes at 12 and 24 months
The aggregated cluster level analyses produced estimates and confidence intervals that were similar to those from the individual level analyses (results not shown). The per protocol analysis produced estimates that were similar to the intention to treat analysis, so the results are not shown.