Long-term survival in patients with advanced immunodeficiency
Objective: To identify prognostic factors associated with survival time in HIV-infected patients with advanced immunodeficiency. Design: Prospective cohort study. Participants: A total of 1,284 HIV-infected patients with serial CD4 count measurements and at least one CD4 cell count ≤ 50 x 106/l (CD4 ≤ 50). Main outcome measure: Survival from initial CD4 cell count ≤ 50 x 106/l. Results: The median survival from initial CD4 ≤ 50 x 106/l was 17.1 months. The risk of death; increased by 2% [95% confidence interval (CI), 1-3] for each year of age, by 70% (95% CI, 3-16) for each 10 x 106/l decrease in CD4 count, and by 14% (95% CI, 9-18) for each 1 g/dl decrease in haemoglobin level. Compared to AIDS-free patients with CD4 ≤ 50 x 106cells/l, the risk of dying was 1.5-fold (95% CI, 1.2-1.9) that of patients who had an AIDS diagnosis for fewer than 3 months prior to CD4 ≤ 50, 1.8-fold for patients with an AIDS diagnosis for 4-11 months prior to CD4 ≤ 50, and twice that of patients with AIDS for ≤ 12 months prior to CD4 ≤ 50. The risk of dying for patients whose rate of CD4 cell decline was > 40 x 106/l per 6 months was 1.7-fold (95% CI, 1.3-2.3) that of patients with an average CD4 cell loss ≤ 40 x 106/l per 6 months, after adjusting for age, haemoglobin and duration of AIDS prior to CD4 ≤ 50 x 106cells/l. A prognostic score was developed from the final multivariate model, based on age at CD4 ≤ 50, haemoglobin at CD4 I 50, duration of AIDS and rate of CD4 decline prior to CD4 ≤ 50. Conclusions: Routinely available clinical and laboratory data including haemoglobin level, rate of CD4 decline and duration of AIDS can be readily translated into a prognostic score and then used to predict the survival experience of an HIV-infected patient with advanced immunodeficiency.