INFLUENCE OF AGE AT INFECTION ON HUMAN-IMMUNODEFICIENCY-VIRUS DISEASEPROGRESSION TO DIFFERENT CLINICAL END-POINTS - THE SEROCO COHORT (1988-1994)

Method. The influence of age at infection on progression of human immu nodeficiency virus (HIV) disease to different clinical endpoints was s tudied among 393 HIV-seropositive adults selected from the French SERO CO cohort; follow-up lasted from January 1988 to November 1994. Select ed patients had a known date of infection and were enrolled shortly af ter seroconversion. Age-associated risk ratios (RR) were estimated usi ng the Cox model (age fitted as a continuous variable and RR expressed for each 10-year increment after adjustment for symptomatic primary i nfection 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 f or 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 C D4 + cell count thresholds for clinical management and treatment initi ation. Risk factors for progression should be assessed according to th e different clinical endpoints.