Background:  Data on long-term changes in CD4 cell count after the start of HAART in therapy-naive patients is limited to 4 to 5 years of follow-up. We evaluated changes in CD4 cell count in a cohort of previously therapy naive patients with 7 years of follow-up after the start of HAART.

Methods:  We selected from the Netherlands ATHENA national observational cohort, 840 therapy-naive HIV-1-infected patients who had started HAART between January 1997 and July 1998 and for whom 7 years of follow-up data were available. Linear regression models were used to find predictors for changes in CD4 cell count at 7 years after starting HAART. In a second analysis, annual changes in CD4 cell count between 1 and 7 years after the start of HAART were compared in patients who had used HAART for at least 6.5 years using repeated measurement models.

Results:  Of the included patients, 84%were male and 69% was of Dutch origin. Median CD4 cell count at the start of HAART was 260 cells/mm³ (IQR 100, 400) and median HIV RNA was 4.9 log₁₀ copies/mL (4.3, 5.4). The mean increase in CD4 cell count 7 years after starting HAART was:  398, 392, 380, 278, and 184 cells/mm³ in those with baseline CD4 count <50, 50 to 200, 201 to 350, 351 to 500, and ≥500 cells/mm³, respectively. The proportion of patients who spent at least 6.5 years on HAART regimens during the first 7 years after the start of HAART was significantly higher in those with lower baseline CD4 cell count:  82%, 84%, 74%, 58%, and 58%, respectively. A lower CD4 cell count and higher HIV RNA level at the start of HAART, Dutch origin, transmission through intravenous drug use and a longer cumulative time on HAART were associated with greater increases in CD4 cell count after 7 years. In 505 continuously HAART-treated patients, the mean annual CD4 cell count change declined significantly with longer follow-up and was 70 cells/mm³ between 1 and 3 years, 30 between 3 and 5, and 10 between 5 and 7 years. The mean annual change between 5 and 7 years was significantly smaller for those with baseline CD4 cell count ≥500 cells/mm³ compared with <500 cells/mm³ (–31 vs 14 cells/mm³ for a patient aged 39 years at the start of HAART, p = 0.001).

Conclusions:  Greater CD4 cell count changes were associated with a longer cumulative time on HAART containing regimens. Between 5 and 7 years on continuous HAART, mean CD4 cell count continued to increase except in patients with ≥500 CD4 cells/mm³ at the start of HAART.