Microalbuminuria on admission for acute exacerbation of COPD as a predictor of all-cause mortality and future exacerbations.

Objectives: Microalbuminuria (MAB) is a sensitive biomarker of cardiovascular risk that is directly associated with cardiovascular events and mortality. Recent studies have evaluated the presence of MAB in patients with stable chronic obstructive pulmonary disease (COPD) or hospitalised for acute exacerbation of COPD (AECOPD).

Methods: We evaluated 320 patients admitted for AECOPD in respiratory medicine departments of two tertiary hospitals. On admission, demographic, clinical and laboratory values and COPD severity were assessed. Patients were evaluated monthly for 1 year, recording new AECOPD and death from any cause.

Results: Patients with documented MAB (urinary albumin excretion of 30-300 mg/24 hours) on admission had worse lung function (forced expiratory volume in 1 s, %) (mean (SD) 34.2 (13.6)% vs 61.5 (16.7)%), higher modified Medical Research Council (3.6 (1.2) vs 2.1 (0.8)), lower 6 min walk test (171 (63) vs 366 (104)) and more hospitalisation days (9 (2.8) vs 4.7 (1.9)) (p < 0.001 for all comparisons). MAB was also correlated with Global Initiative for Chronic Obstructive Lung Disease 2020 COPD stages (p < 0.001). In multivariate regression analysis, MAB was a significant predictor of longer hospitalisation duration (OR 6.847, 95% CI 3.050 to 15.370, p < 0.0001). Twelve-month follow-up revealed that patients with MAB experienced more AECOPDs (4.6 (3.6) vs 2.2 (3.5), p < 0.0001) and deaths, n (%) (52 (36.6) vs 14 (7.8), p < 0.001). Kaplan-Meier survival curves demonstrated that patients with MAB presented with increased mortality, AECOPD and hospitalisation for AECOPD risk at 1 year (p < 0.001 for all comparisons).

Conclusions: The presence of MAB on admission for AECOPD was associated with more severe COPD and prolonged hospitalisation, as well as with higher rates of AECOPD and mortality risk at 1-year follow-up.