Cytomegalovirus seroconversion as a cofactor for progression to AIDS

OBJECTIVE: To study the impact of cytomegalovirus (CMV) seroconversion on HIV-1 disease progression. DESIGN: Follow-up of CMV-seronegative subjects enrolled in the French SEROCO/HEMOCO cohorts of HIV-infected subjects. METHODS: A total of 290 subjects were CMV-seronegative at enrolment in the cohort. Serological testing for CMV infection was done at enrolment and then every 6 months in CMV-seronegative subjects. The person-years method was used to calculate the incidence of CMV seroconversion. After adjustment for age, the CD4+ cell count at enrolment and the HIV exposure group in a Cox model, we studied CMV seroconversion as a time-dependent variable in progression to a CD4+ cell count below 200 x 10(6) cells/l and to clinical AIDS. RESULTS: Overall, 61 CMV seroconversions were observed. The overall incidence rate was 4.4 per 100 person-years [95% confidence interval (CI), 3.3-5.5]. The risk of progression to a CD4+ cell count below 200 x 10(6) cells/l was not increased in CMV seroconverters. However, the risk of progression to AIDS was increased two-fold in CMV seroconverters compared with subjects who remained CMV-seronegative [relative risk (RR) = 2.09; 95% CI, 1.16-3.74; P = 0.01]. CONCLUSION: This analysis of 61 CMV seroconversions, the largest study in the literature, confirms the impact of recent CMV infection on progression to AIDS.