DECREASING FREQUENCY BUT WORSENING MORTALITY OF ACUTE RESPIRATORY-FAILURE SECONDARY TO AIDS-RELATED PNEUMOCYSTIS-CARINII PNEUMONIA

Objective: To describe changes in incidence and outcome of acute respi ratory failure (ARF) due to AIDS-related Pneumocystis carinii pneumoni a (PCP) at a tertiary care center over the 4-year period starting Apri l 1, 1987 with reference to previously reported data from the precedin g 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 variable s. Results: A total of 456 episodes of PCP were diagnosed during the s tudy period. These were compared against 127 cases diagnosed between 1 981 and 1987. The frequency of hospitalization for PCP decreased to 78 % in 1987 to 1991 from 100% in 1981 to 1987 (p less than or equal to 0 .001). A similar decreasing trend was observed with regard to the inci dence 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 mechan ical ventilation decreased from 89% in 1981 to 1987 to 64% in 1987 to 1991 (p<0.001). Despite this, the case fatality rate among mechanicall y ventilated patients increased from 50% in 1981 to 1987 to 89% in 198 7 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 admitte d to the ICU received corticosteroids only after admission to the ICU, following the development of ARF. In contrast, in 1989 to 1990, 50% o f patients were admitted to the ICU already receiving systemic cortico steroids. The rise in the proportion of patients receiving corticoster oids prior to ICU admission between these two intervals was statistica lly significant (p=0.017). Conclusion: Our data show a decreasing freq uency 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 disma l prognosis.