Empirically treated Pneumocystis carinii pneumonia in London, 1983-1989

Abstract

For 227 episodes of Pneumocystis carinii pneumonia (PCP) treated at St Mary's between 1983 and 1989, factors predictive of fatal outcome were age, haemoglobin levels, peripheral lymphocyte count and alveolar-arterial oxygen gradient. Case fatality for the 47 empirically-treated episodes was significantly higher compared with the 180 cytologically proven episodes (55% vs 18%, chi 2 = 25.7, P less than 0.0001). Case fatality for episodes which could not be bronchoscoped was significantly higher compared with bronchoscopy negative cases (66% vs 25%, chi 2 = 4.5, P less than 0.05). Predictive factors for fatal outcome differed significantly for cases which could not be bronchoscoped and cytologically proven cases: haemoglobin level (10.7 g/dl vs 12.0 g/dl, P less than 0.001), lymphocyte count (0.64 x 10(9)/l vs 0.87 x 10(9)/l, P = 0.05) and oxygen gradient (77.7 mmHg vs 58.9 mmHg, P less than 0.02). Such differences were not observed between bronchoscopy negative and cytologically proven cases. Case fatality decreased significantly over time (b = -0.39, SE = 0.14, P less than 0.05). Total and non-fatal first time episodes displayed an inverse relationship between oxygen gradient and time (r = -0.22, P less than 0.006 and r = -0.24, P less than 0.01, respectively). Mean oxygen gradient of fatal episodes for sequential years increased significantly from 73 mmHg in 1983 to 102 mmHg in 1989 (r = 0.92, P less than 0.01). This suggests that medical intervention as well as presentation with less severe disease both contributed to improved case fatality over time.