A stable partnership seems to slow progression to AIDS or death for patients receiving highly active antiretroviral treatment (HAART), a Swiss cohort study has shown. Exactly how such partnerships might affect outcome is purely speculative but warrants further study, especially of the mechanisms suitable for intervention, say its authors.

The prospective study measured outcomes in patients receiving HAART since before 2002 who had complete baseline data three months before the start of treatment—in all, 3736 patients, median age 36 years, 29% women, out of 5350. Patients were asked at six monthly follow ups about stable partnerships—whether they had a stable partner with whom they had had sexual intercourse over the past six months.

Eighty per cent of the cohort (2985) had a stable partner at some time during the study, and progression to AIDS or death was significantly less with stable partnerships, even after adjustment for other influences (adjusted hazard ratio 0.79 (95% confidence interval 0.63 to 0.98)). Also significant was increase in CD4 count by 50 or 100 above baseline (adjusted hazard ratio 1.11, 1.15, respectively). Patients in the study were more likely to be white Europeans, better educated, and to have had antiretroviral treatment before HAART started; they were less likely to be at the stage of progressing to AIDS than those excluded for missing data. Bias is possible, say the authors.

Social support is known generally to influence mortality but whether partner support affects outcome in HIV infection is not—hence the reason for this study.