Predictors of Adverse Outcome in Patients Hospitalised for Exacerbation of Chronic Obstructive Pulmonary Disease

Abstract

Background: It is crucial to identify risk factors for poor evolution of patients admitted to hospital with chronic obstructive pulmonary disease (COPD) in order to provide adequate intensive therapy and closer follow-up. Objectives: To identify predictors of adverse outcomes in patients hospitalised for exacerbation of COPD. Methods: A prospective, observational study was conducted in patients admitted for exacerbation of COPD. Demographic and clinical parameters were evaluated, including different multidimensional prognostic scores. Adverse outcomes included the following: death during hospitalisation or 1-month follow-up, intensive care unit admission, invasive or non-invasive mechanical ventilation, prolonged hospitalisation (>11 days) and COPD-related emergency visit or readmission within 1 month after discharge. Univariate and multivariate analysis were performed. Results: Of 155 patients included, an adverse outcome occurred in 69 (45%). Patients with an adverse outcome had lower forced expiratory volume in 1 s (p = 0.004) and more frequent exacerbations (p = 0.011), more frequently used oxygen at home (p = 0.042) and presented with lower pH (p < 0.001), lower ratio of arterial oxygen pressure to the fraction of inspired oxygen (p = 0.006), higher arterial carbon dioxide pressure (p < 0.001) and a worse score on several prognostic indices at admission. Independent predictors of adverse outcome were exacerbation of COPD in the previous year [odds ratio 3.9, 95% confidence interval (CI) 1.6–9.9; p = 0.004], hypercapnia (odds ratio 9.4, 95% CI 3.7–23.6; p < 0.001) and hypoxaemia (odds ratio 4.3, 95% CI 1.5–12.6; p = 0.008). In the presence of all three characteristics, the probability of an adverse outcome was 95%, while hypercapnia was the strongest prognostic factor with a risk of 54%. Conclusions: Patients with previous exacerbation of COPD, hypercapnia and hypoxaemia had the highest risk of an unfavourable evolution. The calculation of prognostic indices did not provide additional discriminative power.