LAUSR

The study by Sharafkhaneh et al. (1) aimed to determine whether admission of patients with chronic obstructive pulmonary disease (COPD) and pneumonia (PCOPD) was associated with a higher mortality than admission for either acute COPD exacerbation without pneumonia (AECOPD) or pneumonia without COPD (PNA). The study included 7,154 hospitalized patients at 16 hospitals in the Veterans Health Administration (VHA) network during the fiscal years of 2000– 2012. The results showed an increase in inpatient mortality for PCOPD (13.2%), when compared to PNA (9.5%), or AECOPD (4.8%), p < 0.0001. The same pattern persisted at 30 days postdischarge (PCOPD 14.6%, PNA 12.4% and AECOPD 6.7%; p < 0.0001). The authors did not assess the chest imaging or its report for the presence of infiltrate to confirm the diagnosis of pneumonia or have access to pulmonary function test data to confirm the diagnosis of COPD, which represented important limitations already mentioned by the authors. Assuming that the diagnoses were made correctly, the higher mortality in PCOPD patients was expected as they were more likely to have co-morbid conditions that increase the risk of dying including heart failure [which itself is considered a risk factor for pneumonia (2,3)], coronary artery disease, atrial arrhythmias (particularly atrial fibrillation), pulmonary thromboembolism, home oxygen preinception, and chronic renal failure. These, along with COPD or pneumonia, were independently associated with mortality during inception admission and at long term (Tables 5 and 4, respectively). However, no interaction terms for pneumonia and COPD were included in the analysis to assess for synergistic effect. Therefore, question still remains as to whether the higher mortality in PCOPD patients is attributable to