Chronic obstructive pulmonary disease is associated with a higher incidence of acute kidney injury in non-cardiac but not in cardiac surgery ICU-patients: a retrospective MIMIC-III database analysis

PURPOSE: Acute kidney injury (AKI) and chronic obstructive pulmonary disease (COPD) are both associated with high mortality. We hypothesized that COPD impacts the incidence of AKI and the outcome of surgical intensive care unit (ICU)-patients. MATERIALS AND METHODS: We analyzed data of surgical ICU-patients from the Medical-Information-Mart-for-Intensive-Care-III-database. We compared the incidence of AKI, in-hospital-mortality, ICU-and hospital-length-of-stay (ICU-LOS, HLOS) in patients with and without COPD. In a subgroup analysis, we compared the outcomes of patients undergoing cardiac (CS) and non-cardiac surgery (NCS). RESULTS: The data of 21,720 cases were analyzed, 9.7 % suffered from COPD. COPD-patients were younger compared to patients without COPD (64years(52-75)vs.71years(63-78),p < 0.001). Males were more frequently represented in both groups (58.3 %vs.61.2 %,p = 0.009). COPD-patients had a higher incidence of AKI (24.2 %vs.19.7 %,p < 0.001), higher in-hospital-mortality (8.7 % vs.6.4 %,p < 0.001), longer ICU-LOS (3.1days(IQR,1.6-7.0)vs.2.3days(IQR,1.3-5.0),p < 0.001), and HLOS (10days(IQR,6-17)vs.8days(IQR,5-15),p < 0.001). Multivariable analyses could not confirm a higher risk for AKI in surgical COPD-patients but for all other outcomes (in-hospital mortality,OR:1.59,95 %CI:1.24-2.04,p < 0.001; ICU-LOS,beta:1.1, 95 %CI:0.6-2.3,p < 0.001; HLOS,beta:1.7,95 %CI:0.9-2.4,p < 0.001). Subgroup analyses revealed that COPD was associated with a higher risk of AKI (OR,1.24,95 %CI:1.01-1.51,p = 0.038), longer ICU-LOS (beta:0.9,95 %CI:0.3-1.5,p = 0.006) and HLOS (beta:1.4,95 %CI:0.2-2.5,p = 0.018) but not with a higher risk for in-hospital mortality in NCS-patients. In CS-patients on the other hand, COPD was associated with a higher risk for in-hospital mortality (OR,1.73,95 %CI:1.02-2.94,p = 0.043) but neither for AKI, longer ICU-LOS or HLOS. CONCLUSIONS: COPD has a different impact on outcomes in CS- and NCS-patients. While COPD was associated with a higher risk for in-hospital mortality in CS-patients, COPD was associated with a higher risk of AKI, longer ICU-LOS and HLOS in NCS-patients.