QUANTITATIVE HIV-1 RNA AS A MARKER OF CLINICAL STABILITY AND SURVIVALIN A COHORT OF 302 PATIENTS WITH A MEAN CD4 CELL COUNT OF 300X10(6) L/

Objective: To analyse plasma HIV-1 RNA levels as a marker of clinical stability and survival in a cohort of HIV-infected patients whose time of seroconversion is unknown. Design: Retrospective cohort study. Set ting: Retrovirology laboratory and AIDS Unit in a teaching hospital. P atients: A total of 916 samples from 302 patients, most on antiretrovi ral therapy, were analysed. Mean initial CD4 cell counts and HIV-1 RNA were 299 x 10(6)/l (range: 0-1600) and 134 261 copies/ml (range: < 20 0-4 300 000), respectively. Sixty-six cases had been diagnosed previou sly with AIDS. Methods: Analysis of progression to AIDS and survival, according to initial and longitudinal viral load (VL) and CD4 cell cou nt measurements was performed by Kaplan-Meier test. Relative risks wer e calculated by Cox's proportional hazards model. Results: During a me an follow-up of 444 +/- 309 days, 29 patients developed AIDS and 21 di ed. Relative risk (RR) of progression related to the group with VL < 3 5 000 was: 10.4 when CD4 greater than or equal to 250 x 10(6)/l and VL greater than or equal to 35 000 (P = 0.001); and 45.3 when CD4 < 250 x 10(6)/l and VL greater than or equal to 35 000 (P < 0.0001). Cumulat ive probability of progression was: 0%, 0% and 12.3%, at the first, se cond and third year respectively, for patients with all their sequenti al VL determinations < 60 000; acid 13.3%, 34.7% and 79.3% for patient s who did not maintain VL values always < 60 000 (RR = 23; P < 0.0001) . The minimum value of VL that reached statistical significance for th e survival analysis was 100 000 copies/ml (P < 0.0001). Conclusions: V L greater than or equal to or < 35 000 is a better discriminant for pr ogression than a CD4 cell count greater than or equal to or < 250 x 10 (6)/l. Sequential VL determinations < 60 000 are associated with a bet ter prognosis.