One-year mortality and readmission risks following hospitalization for acute exacerbation of chronic obstructive pulmonary disease based on the types of acute respiratory failure: An observational study

Few studies have examined the risk factors associated with the type of acute respiratory failure (ARF) in patients with acute exacerbation of chronic obstructive pulmonary disease (COPD). This study evaluated the clinical characteristics and prognosis of patients hospitalized for acute exacerbation of COPD based on the type of ARF. The medical charts of hospitalized patients with acute exacerbation of COPD between 2016 and 2021 were retrospectively reviewed. We classified ARF into 2 types: type 1 ARF with PaO2 < 60 mm Hg in room air or a ratio of arterial partial pressure to fractional inspired oxygen < 300, and type 2 ARF with PaCO2 > 45 mm Hg and arterial pH < 7.35. A total of 435 patients were enrolled in study, including 170 participants without ARF, 165 with type 1 ARF, and 100 with type 2 ARF. Compared with the non-ARF group, the frequency of high-flow nasal cannula, noninvasive ventilation, intensive care unit admissions, and in-hospital deaths was higher in the ARF group compared with the non-ARF group. The ARF group had higher 1-year mortality group (hazard ratio [HR], 2.809; 95% confidence interval [CI], 1.099-7.180; P = .031) and readmission within 1-year rates (HR, 1.561; 95% CI, 1.061-2.295; P = .024) than the non-ARF group. The type 1 ARF group had a higher risk of 1-year mortality (HR, 3.022; 95% CI, 1.041-8.774; P = .042) and hospital readmission within 1-year (HR, 2.053; 95% CI, 1.230-3.428; P = .006) compared with the non-ARF group. There was no difference in mortality and readmission rates between the type 1 and type 2 ARF groups. In conclusion, patients with type 1 ARF rather than type 2 ARF had higher mortality and readmission rates than those without ARF. The prognoses of patients with type 1 and type 2 ARF were similar.