VALVE OF HIV-1 VIRAL LOAD AND CD4 LYMPHOC YTE COUNT AS DETERMINANTS OF PROGRESSION TO AIDS AND SURVIVAL

BACKGROUND: HIV-I viral load is regarded as a better surrogate marker for progression and death than CD4+ cell counts. Both markers are anal ysed in a cohort of patients with unknown seroconversion date and adva nced HIV infection. PATIENTS AND METHODS: Retrospective cohort analysi s of 421 patients, most on antirefroviral therapy, with a median initi al CD4+ cell count of 209 X 10(6)/l and a median initial viral load of 4.7 log copies/ml. One thousand two hundred and eighty-six samples we re analysed. Univariate and bivariate analysis were performed with ini tial and sequential CD4+ cell counts and viral load values to estimate the risk of progression and death by Cox regression models. RESULTS: After a median follow up of 763 days, 124 patients developed AIDS and 117 died. Relative risks of progression related to the group that main tained viral load values always < 35.000 copies/ml were: 5-fold (95% C I: 1.4-17.0; p < 0.05) for patients with any viral load value > 35.000 copies/ml but always < 200.000 copies/ml; and 13.6 fold (95% CI: 5.4- 34.2; p < 0.0001) for patients who could not maintain viral load < 200 .000 copies/ml. CD4+ counts = 100 X 10(6)/l and viral load = 220.000 c opies/ml were the threshold values that best fitted to estimate the pr obability of survival by a bivariate analysis. CONCLUSIONS: The mainte nance of sequential viral load values < 35.000 copies/ml is associated with a lower risk of progression. The maintenance of sequential viral load values < 150.000 copies/ml is associated with higher short-term survival rates.