ALB and chronic obstructive pulmonary disease: BMI: body mass index, urine ACR: ratio of urine albumin to urine creatinine, FEV1: forced expiratory volume in 1 second, FVC: forced vital capacity, FEV1/FVC: ratio of FEV1 to FVC, GOLD stage: Global Initiative for Chronic Obstructive Lung Disease stage, CAT score: COPD Assessment Test score.