“…These studies had differing definitions for diagnosis (laboratory-confirmed PCP or "empirical" PCP) and survival (1 or 3 months); in addition, each study examined only a small number of risk factors. By contrast, several single-center studies, each of which describe !150 patients, have identified increasing patient age [8,9], prior receipt of PCP prophylaxis [10], poor oxygenation at hospitalization [11,12], elevated lactate dehydrogenase enzyme levels [13], low hemoglobin [14] and serum albumin [15] levels, bacterial infection [12], cytomegalovirus (CMV) infection [8], neutrophilia in bronchoalveolar lavage (BAL) fluid [16,17], comorbidity [18,19], pneumothorax [20][21][22], and the need for mechanical ventilation [20][21][22] as being associated with death. These studies are inconsistent, because not all of these studies show these factors to be associated with mortality.…”