Acute kidney injury in hospitalized patients with nonexacerbated chronic obstructive pulmonary disease

Background The epidemiology of acute kidney injury (AKI) in nonexacerbated chronic obstructive pulmonary disease (NECOPD) patients is unknown. This study investigated the factors associated with AKI and the association between AKI and in-hospital mortality in the hospitalized NECOPD population. Methods The electronic medical records of 2897 patients hospitalized with NECOPD were analyzed retrospectively. Demographic information, medicine used before AKI, diagnosis records and laboratory data were collected. AKI was classified as community-acquired (CA-) or hospital-acquired (HA-) AKI according to the serum creatinine criteria. Risk factors for HA-AKI and in-hospital mortality were analyzed by logistic regression analyses. To avoid an interaction between cor pulmonale and AKI, the association between AKI and in-hospital morality was further analyzed with cor pulmonale stratification. Results The incidence rates of CA- and HA-AKI were 7.1 and 12.0%, respectively. Increased age, female sex, cor pulmonale comorbidity, chronic kidney disease stage, diuretic and glycopeptide use before AKI and iodine-containing contrast medium exposure were independently associated with HA-AKI. A total of 5.7% of the patients died. After adjustment for age, sex, cor pulmonale, chronic kidney disease, Charlson comorbidity index score (without renal disease) and hemoglobin level, HA-AKI was an independent risk factor for in-hospital mortality [OR 13.909 (95% CI 8.699–22.238) in non-cor pulmonale subgroup; OR 26.604 (95% CI 12.166–58.176) in cor pulmonale subgroup], whereas CA-AKI was not. Conclusions AKI is common in the NECOPD population. Diuretics and contrast media are associated with HA-AKI in this population. The patients with HA-AKI have a higher mortality risk than the patients without AKI.