Validation of the modified multisystem organ failure score as a predictor of mortality in patients with AIDS-related Pneumocystis carinii pneumonia and respiratory failure.

STUDY OBJECTIVES To validate a previously developed multisystem organ failure (MSOF) score with and without the addition of the lactate dehydrogenase (LDH) level as a predictor of survival to hospital discharge in patients with AIDS-related Pneumocystis carinii pneumonia (PCP) and acute respiratory failure (ARF). DESIGN Retrospective chart review between April 1, 1991, and September 30, 1996. SETTING University-affiliated tertiary care center in downtown Vancouver, British Columbia, Canada. PATIENTS All patients with PCP-related ARF admitted to the ICU of St. Paul's Hospital during the study period. INTERVENTIONS As putative prognostic instruments, data were extracted regarding the APACHE II (acute physiology and chronic health evaluation II), acute lung injury (ALI), AIDS, and modified MSOF scores, as well as LDH levels, at entry to the ICU. Patients were stratified based on an LDH level of < or > or = 2,000 U/L and this threshold was assessed in its predictability of outcome when added to each of the above scores. For APACHE II, the score was categorized in six groups and evaluated with and without inclusion of the LDH. Receiver operating characteristic curves were constructed for LDH and for each score with and without the LDH level to assess accuracy of prediction. The area under each curve was calculated and compared to estimate the statistical significance of observed differences. MEASUREMENTS AND RESULTS There were 40 admissions to the ICU of 38 patients with 52.5% mortality. The ALI and AIDS scores were not predictive of outcome. The modified MSOF and APACHE II scores were significant predictors of survival and the performance of both was enhanced by the addition of LDH. CONCLUSIONS Both the APACHE II and the modified MSOF scores were significant predictors of outcome in the patient population studied. These results validate the modified MSOF score as an effective predictor of survival to hospital discharge among patients with AIDS-related PCP who develop ARF and the performance of the score is enhanced by the addition of the LDH level.