Pneumonia Is Associated with Increased Mortality in Hospitalized COPD Patients: A Systematic Review and Meta-Analysis.

BACKGROUND Patients with chronic obstructive pulmonary disease (COPD) are at a heightened risk of pneumonia. Whether coexisting community-acquired pneumonia (CAP) can predict increased mortality in hospitalized COPD patients is still controversial. OBJECTIVE This systematic review and meta-analysis aims to assess the association between CAP and mortality and morbidity in COPD patients hospitalized for acute worsening of respiratory symptoms. METHODS In this review, cohort studies and case-control studies investigating the impact of CAP in hospitalized COPD patients were retrieved from 4 electronic databases from inception until December 2019. Methodological quality of included studies was assessed using Newcastle-Ottawa Quality Assessment Scale. The primary outcome was mortality. The secondary outcomes included length of hospital stay, need for mechanical ventilation, intensive care unit (ICU) admission, length of ICU stay, and readmission rate. The Mantel-Haenszel method and inverse variance method were used to calculate pooled relative risk (RR) and mean difference (MD), respectively. RESULTS A total of 18 studies were included. The presence of CAP was associated with higher mortality (RR = 1.85; 95% CI: 1.50-2.30; p < 0.00001), longer length of hospital stay (MD = 1.89; 95% CI: 1.19-2.59; p < 0.00001), more need for mechanical ventilation (RR = 1.48; 95% CI: 1.32-1.67; p < 0.00001), and more ICU admissions (RR = 1.58; 95% CI: 1.24-2.03; p = 0.0002) in hospitalized COPD patients. CAP was not associated with longer ICU stay (MD = 5.2; 95% CI: -2.35 to 12.74; p = 0.18) or higher readmission rate (RR = 1.02; 95% CI: 0.96-1.09; p = 0.47). CONCLUSION Coexisting CAP may be associated with increased mortality and morbidity in hospitalized COPD patients, so radiological confirmation of CAP should be required and more attention should be paid to these patients.