Background: There are known to be wide differences in the prognosis of patients with a diagnosis of AIDS. In this study of 6578 patients with AIDS form 17 European centres, we develop a ranking of AIDS-defining illnesses, and determine how well this ranking holds after adjustment for potential confounding variables.
Methods: Survival from each AIDS-defining event was calculated and ranked using Kaplan-Meier estimation of median survival. Cox proportional hazards models with each disease modelled as a time dependant covariate were used to determine the risk of death after each diagnosis, before and after adjustment for potential confounders.
Results: Median survival after an initial AIDS-defining diagnosis of progressive multifocal leukoencephalopathy and malignant lymphoma was particularly poor (2 and 5 months respectively), while the longest median survival occurred after initial AIDS-defining illnesses of Kaposi's sarcoma and extrapulmonary tuberculosis (17 and 22 months respectively) Patients diagnosed with a primary brain lymphoma had shorter median survival times than patients with a peripheral lymphoma (median survival of 1 month and 4 months respectively P < 0.0001). In general, median survival in patients with cutaneous Kaposi's sarcoma (skin, oral) was between two and four times longer than patients with systemic involvement The ranking of diseases was found to be generally similar after adjustment for all potential confounders.
Conclusions: AIDS-defining events can be grouped into three categories with median survival after diagnosis of < 6 months. 6-12 months and > 12 months. The assigned ranking of disease would not be altered by prognostic factors such as age or CD4 lymphocyte count. These results have important implications in the design of clinical trials and patient management.