Objective: To describe changes in incidence and outcome of acute respiratory failure (ARF) due to AIDS-related Pneumocystis carinii pneumonia (PCP) at a tertiary care center over the 4-year period starting April 1, 1987 with reference to previously reported data from the preceding 6 years.
Methods: All patients admitted to St. Paul's hospital with a diagnosis of AIDS-related PCP during the study period were reviewed with regard to diagnostic, clinical, therapeutic, and outcome variables.
Results: A total of 456 episodes of PCP were diagnosed during the study period. These were compared against 127 cases diagnosed between 1981 and 1987. The frequency of hospitalization for PCP decreased to 78% in 1987 to 1991 from 100% in 1981 to 1987 (p < or = 0.001). A similar decreasing trend was observed with regard to the incidence of PCP-related ARF that declined from 21% in 1981 to 1987 to 9% in 1987 to 1991 (p = 0.009). Despite this, overall PCP-related mortality remained stable at 12% in 1981 to 1987 and 9% in 1987 to 1991 (p = 0.26). The proportion of patients with PCP-related ARF who received mechanical ventilation decreased from 89% in 1981 to 1987 to 64% in 1987 to 1991 (p < 0.001). Despite this, the case fatality rate among mechanically ventilated patients increased from 50% in 1981 to 1987 to 89% in 1987 to 1991 (p = 0.003). These changes were associated with a significant change in the pattern of use of corticosteroids as adjunctive therapy for AIDS-related PCP. In 1985 to 1986, nearly 100% of patients admitted to the ICU received corticosteroids only after admission to the ICU, following the development of ARF. In contrast, in 1989 to 1990, 50% of patients were admitted to the ICU already receiving systemic corticosteroids. The rise in the proportion of patients receiving corticosteroids prior to ICU admission between these two intervals was statistically significant (p = 0.017).
Conclusion: Our data show a decreasing frequency but a worsening mortality of ARF secondary to AIDS-related PCP. We conclude that ARF secondary to AIDS-related PCP developing despite maximal therapy, including adjunctive corticosteroids, carries a dismal prognosis.