ALB and chronic obstructive pulmonary disease: Independent risk factors for death were the following (hazard ratio, 95% CI): age (1.83 per decade, 1.47–2.28), cardiovascular disease (2.63, 1.61–4.32), COPD (2.09, 1.27–3.45), immunocompromization (1.98, 1.17–3.37), and low serum albumin level at admission (0.75 per 5g/L higher, 0.58–0.96), whereas active smoking was protective (0.32, 0.14–0.74); active smokers were younger than non-smokers (P < 0.001).