Objective: To estimate median survival and changes in survival in patients diagnosed as having AIDS.
Design: Prospective observational study.
Setting: Clinics in two large London hospitals.
Subjects: 2625 patients with AIDS seen between 1982 and July 1995.
Main outcome measures: Survival, estimated using lifetable analyses, and factors associated with survival, identified from Cox proportional hazards models.
Results: Median survival (20 months) was longer than previous estimates. The CD4 lymphocyte count at or before initial AIDS defining illness decreased significantly over time from 90 x 10(6)/1 during 1987 or earlier to 40 x 10(6)/1 during 1994 and 1995 (P < 0.0001). In the first three months after diagnosis, patients in whom AIDS was diagnosed after 1987 had a much lower risk of death (relative risk 0.44, 95% confidence interval 0.22 to 0.86; P = 0.017) than patients diagnosed before 1987. When the diagnosis was based on oesophageal candidiasis or Kaposi's sarcoma, patients had a lower risk of death than when the diagnosis was based on Pneumocystis carinii pneumonia (0.21 (0.07 to 0.59). P = 0.0030 and 0.37 (0.16 to 0.83), P = 0.016). Three months after AIDS diagnosis, the risk of death was similar in patients whose diagnosis was made after and before 1987 (1.02 (0.79 to 1.31), P = 0.91). There were no differences in survival between patients diagnosed during 1988-90, 1991-3, or 1994-5.
Conclusions: In later years, patients were much more likely to survive their initial illness, but long term survival has remained poor. The decrease in CD4 lymphocyte count at AIDS diagnosis indicates that patients are being diagnosed as having AIDS at ever more advanced stages of immunodeficiency.