The Long-term Pneumonia Mortality Index: an international multicenter derivation and validation study for patients with community-acquired pneumonia

RATIONALE: Long-term mortality after hospital discharge in community-acquired pneumonia (CAP) is a neglected issue. A validated, accurate score predicting mortality is needed. OBJECTIVE: To derive and validate the Long-term Pneumonia Mortality Index (L-PMI). METHODS: L-PMI derivation used data from a Spanish multicenter prospective study on CAP with a 1-year follow-up. A logistic regression model for predicting 1-year mortality risk was developed. Performance of the model was assessed by estimating the area under the receiver operating characteristic curve (AUC). The model was externally validated using 2 independent multicenter CAP cohorts from Germany and the United States (USA), and one COVID-19 pneumonia cohort from Spain. We then derived a score from the model to ease its application. MEASUREMENTS AND MAIN RESULTS: The long-term mortality rate after discharge was 6.3%, 4.4%, 17.4%, and 3.6% in the derivation, CAPNETZ (only 6 months of follow-up), USA, and COVID-19 cohorts, respectively. The L-PMI included age, smoking history, nursing home residency, Charlson Comorbidity Index score, CURB-65 score, use of noninvasive or invasive mechanical ventilation, and in-hospital cardiovascular events. The L-PMI showed high discrimination for mortality in the derivation cohort (AUC, 0.82 [95% CI, 0.78-0.85]). In the validation cohorts, the AUC (95% CI) ranged from 0.78 (0.73-0.83) to 0.75 (0.73-0.77) for the CAPNETZ and USA cohorts, respectively, and 0.88 (0.84-0.93) for the COVID-19 cohort. L-PMI allows classification of patients according to their mortality risk into low-, intermediate-, and high-risk groups. CONCLUSIONS: The L-PMI is a novel clinical prediction score that identifies pneumonia patients at risk of mortality up to 1 year after discharge.