Mortality rates in people dually infected with HIV-1/2 and those infected with either HIV-1 or HIV-2: a systematic review and meta-analysis

Objective: As compared to HIV-1 infection, HIV-2 is less transmissible, disease progression is slower, and the mortality risk is lower. It has been suggested that HIV-2 infection inhibits the progression of HIV-1 in individuals dually infected by HIV-1 and HIV-2 (HIV-D). We examined whether the mortality rates in dually infected individuals differ from those in persons infected with either HIV-1 or HIV-2. Design: We conducted a systematic review and meta-analysis. Methods: Medline and Embase databases were searched for studies that reported the number of deaths and person-years of observation (PY) for at least two of the three HIV groups (i.e. HIV-1, HIV-2, and HIV-D). Meta-analyses were then performed with random-effects models, estimating combined mortality rate ratios (MRRs). Results: Of the 631 identified titles, six articles were included in the meta-analysis of HIV-D-infected individuals versus HIV-mono-infected persons, and seven were included in the analysis of HIV-1-mono-infected versus HIV-2-mono-infected individuals. The overall MRR of those infected with HIV-D versus HIV-1 was 1.11 [95% confidence interval (CI) 0.95-1.30]. The overall MRR of those infected with HIV-D versus HIV-2 was 1.81 (95% CI 1.43-2.30) and the MRR of those infected with HIV-1 versus HIV-2 was 1.86 (95% CI 1.44-2.39). Conclusion: HIV-2-mono-infected persons have a lower mortality rate than those mono-infected with HIV-1 and those with HIV-D. There is no evidence that HIV-2 delays progression to death in HIV-D-infected individuals.