Predictors of adverse outcome in patients hospitalised for exacerbation of chronic obstructive pulmonary disease.

Matkovic, Zinka; Huerta, Arturo; Soler, Nestor; Domingo, Rebeca; Gabarrús, Albert; Torres, Antoni; Miravitlles, Marc

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.