Impact of renal dysfunction on in-hospital mortality of patients with severe chronic obstructive pulmonary disease: a single-center Italian study

We conducted a study, based on discharge hospital sheets [International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM)], in order to evaluate the relationship between chronic kidney disease (CKD), acute kidney injury (AKI), multi-morbidity, and in-hospital mortality (IHM).

We analyzed 7073 subjects with COPD exacerbation; they were more frequently male (56.9 vs 43.1 %), and mean age was 76.7 ± 9.8 years. Diagnosis of CKD was present in 771 patients (10.9 %), while AKI was diagnosed in 354 cases (5 %). A total of 554 patients (7.8 %) died during hospitalization, and LOS was 10.3 ± 11.2 days (median 8 days); the CCI corrected for CKD was 2.30 ± 1.65. Univariate analysis showed that IHM group had higher age (81.2 ± 7.9 vs 76.3 ± 9.9 years, p < 0.001), CCI (2.61 ± 2.21 vs 2.28 ± 1.62, p = 0.001), and LOS (11.1 ± 15.1 vs 10.3 ± 10.8 days, p = 0.001) and developed AKI more frequently (16.6 vs 4 %, p < 0.001) than survivors. Multivariate logistic regression analysis showed an independent association of IHM with age (OR 1.063; 95 % CI 1.050–1.075, p < 0.001), male sex (OR 1.229; 95 % CI 1.016–1.486, p = 0.033), logCCI (OR 2.051; 95 % CI 1.419–2.964, p < 0.001), and AKI (OR 3.849; 95 % CI 2.874–5.155, p < 0.001).

Acute kidney injury (AKI) represents a very important predictive factor of IHM in male older adult with multi-morbidity admitted because of COPD exacerbations.