Influence of age at infection on human immunodeficiency virus disease progression to different clinical endpoints: the SEROCO cohort (1988- 1994). The Seroco Study Group
International Journal of Epidemiology
Method. The influence of age at infection on progression of human immunodeficiency virus (HIV) disease to different clinical endpoints was studied among 393 HIV-seropositive adults selected from the French SEROCO cohort; follow-up lasted from January 1988 to November 1994. Selected patients had a known date of infection and were enrolled shortly after seroconversion. Age-associated risk ratios (RR) were estimated using the Cox model (age fitted as a continuous variable and RR expressed for each
... expressed for each 10-year increment after adjustment for symptomatic primary infection and sexual preference). Results. Age had a weak influence on progression from the date of infection to the first category B event (crude RR = 1.15; adjusted RR = 1.09; 95% confidence interval [CI] : 0.89-1.36) but a marked influence on progression from the first category B to the first category C event (crude RR = 1.95; adjusted RR = 1.97; 95% CI : 1.37-2.79). Similar results were obtained after adjustment for the CD4 + cell count at enrolment. A qualitative CD4 + cell defect could explain the influence of age, but this remains to be confirmed. Conclusion. Age at infection should be included in the definition of CD4 + cell count thresholds for clinical management and treatment initiation. Risk factors for progression should be assessed according to the different clinical endpoints.