Clinical relevance of cytomegalovirus viraemia(*,†)

BACKGROUND: Using new sensitive quantitative polymerase chain reaction (PCR) assays, cytomegalovirus (CMV) DNA is often detectable in the plasma of immunosuppressed patients. We investigated the prognostic value of a positive CMV DNA test for the development of CMV end-organ disease, other AIDS-defining events and mortality. METHODS: A survival analysis was performed, using the Kaplan-Meier method and Cox proportional hazards models, for patients prospectively followed in the Swiss HIV Cohort Study, from January 1996 to December 2007, who were CMV-seropositive, had a CD4 count of >/= 100 cells/muL, and had a plasma sample available for the measurement of baseline CMV DNA with an ultrasensitive PCR. The outcome analysed was an AIDS-defining event, including CMV end-organ disease, or death. Variables analysed at the time of CMV measurement were demographic variables, CD4 cell counts, HIV-1 RNA loads, and use and type of highly active antiretroviral therapy (HAART). RESULTS: Of 1128 patients, 208 (18%) presented an AIDS-defining event and 246 (22%) died. A total of 368 patients (34% of samples) had detectable CMV DNA at baseline, with DNA concentrations of up to 38 800 copies/mL. In the multivariate analysis, CMV DNA predicted evolution not only towards CMV end-organ disease [hazard ratio (HR) 12.6; 95% confidence interval (CI) 4.27-37.41], but also towards other AIDS-defining events (HR 2.6; 95% CI 1.60-4.33) and death (HR 1.9; 95% CI 1.10-3.34). CONCLUSION: Quantitative CMV DNA detected in the plasma of HIV-infected patients with CD4 counts >/= 100 cells/muL is a predictor for HIV disease progression, CMV disease and death. A single low value of 80 copies/mL identifies patients at low but significantly increased risk during the following months, after the measurement.