Lack of evidence of a stable viral load set-point in early stage asymptomatic patients with chronic HIV-1 infection.

Methods: Medical visits were performed at least every 6 months including routine blood analysis, viral load and CD4+ T-cell count. HIV-1 RNA was measured in frozen (-70 degrees C) plasma samples using PCR. Patients were classified into three groups according to baseline viral load: group A, 200 copies/ml (undetectable); group B, 201-2000 copies/ml; group C, 2001-5000 copies/ml. A survival analysis and a Cox regression model were performed to assess the influence of viral and host factors in the increase of baseline viral load. The endpoint was the time to increase viral load to a stable level > 0.5 log10 copies/ml above baseline viral load in groups B and C and to a stable detectable viral load (> 200 copies/ml) in group A.

Results: A cohort of 114 patients with viral load below 5000 copies/ml was followed for a median of 12 months (6-42 months). Overall, 22 (19%) out of 114 patients had an increase > 0.5 log10 copies/ml of baseline viral load. Baseline viral load increased in two (5%) out of 37 patients in group A, four (12%) out of 33 patients in group B, and 16 (36%) out of 44 patients in group C (survival analysis, P0.002). Patients of group C had a eightfold higher risk of increasing baseline viral load than patients in the other two groups pooled together (hazards ratio, 8.28; 95% confidence interval, 1.78-38; P = 0.006). Patients with an increase of viral load to the virological endpoint had a threefold higher risk of decreasing baseline CD4+ T-cell counts > 100 x 10(6)/I than patients with stable viral load (hazards ratio, 2.78; 95% confidence interval, 1.12-14; P = 0.03).

Conclusion: A cohort of 114 patients with viral load below 5000 copies/ml was followed for a median of 12 months (6-42 months). Overall, 22 (19%) out of 114 patients had an increase > 0.5 log10 copies/ml of baseline viral load. Baseline viral load increased in two (5%) out of 37 patients in group A, four (12%) out of 33 patients in group B, and 16 (36%) out of 44 patients in group C (survival analysis, P0.002). Patients of group C had a eightfold higher risk of increasing baseline viral load than patients in the other two groups pooled together (hazards ratio, 8.28; 95% confidence interval, 1.78-38; P = 0.006). Patients with an increase of viral load to the virological endpoint had a threefold higher risk of decreasing baseline CD4+ T-cell counts > 100 x 10(6)/I than patients with stable viral load (hazards ratio, 2.78; 95% confidence interval, 1.12-14; P = 0.03).