Background Although HIV-1 and HIV-2 share the same transmission routes, HIV-2 is less transmissible, it has a longer median time from infection to AIDS, and the associated mortality risk is lower. It has been suggested that HIV-2 infection inhibits HIV-1 disease progression in dually infected (HIV-D) individuals, but whether the mortality rate of HIV-D infected individuals differs from that of HIV-1 mono-infected individuals is still not clear. We conducted a systematic review and meta-analysis on HIV mortality.

Methods Medline and Embase databases were searched. The inclusion criteria for studies were an antiretroviral therapy-naïve population during follow-up, reporting mortality data and person-years of observation (pyo) for at least two of the three HIV-groups, i.e. a HIV-1 mono and/or a HIV-2 mono and/or a HIV-D infected group. Meta-analyses were performed using random effects models, estimating combined mortality rate ratios (MRRs).

Results Of the 631 identified titles, 7 articles met the inclusion criteria. Of these, 6 articles were included in the meta-analysis of HIV-D versus HIV mono-infected and 7 were included in the analysis of HIV-1 versus HIV-2 mono-infected people. The overall MRR of HIV-D versus HIV-1 was 1.11 (95% CI 0.95–1.30). The overall MRR of HIV-D versus HIV-2 was 1.81 (95% CI 1.43–2.30) and the MRR of HIV-1 versus HIV-2 was 1.86 (95% CI 1.44–2.39)

Conclusion The mortality rate of HIV-D infected individuals did not significantly differ from the mortality rate of HIV-1 mono-infected individuals. The mortality rates of both HIV-1 mono-infected and HIV-D infected individuals were significantly higher than the rate among HIV-2 mono-infected individuals. Therefore, we conclude that HIV-2 mono-infected have a lower mortality rate than HIV-1 infected individuals, but there is no evidence that HIV-D infected individuals survive longer than HIV-1 mono-infected individuals.