Impact of early acute kidney injury on 30-day mortality in intensive care unit patients with chronic obstructive pulmonary disease: a retrospective study using MIMIC-IV.

Background: Chronic obstructive pulmonary disease (COPD) is one of the leading causes of death worldwide, and acute kidney injury (AKI) is one of the most common comorbidities in patients with COPD. However, the impact of AKI occurring within 2 days of COPD diagnosis is unclear. Therefore, this study aimed to assess the impact of a 2-day onset of AKI on COPD patient outcomes using the Medical Information Mart for Intensive Care-IV (MIMIC-IV) database. Methods: This retrospective study is based on version 2.2 of the MIMIC-IV database. We collected clinical data and 30-day all-cause mortality data for patients with COPD in the intensive care unit (ICU), who met the diagnostic criteria for COPD upon admission between 2008 and 2019. We used the International Classification of Diseases, 10th Revision (ICD-10) (codes J44, J440, J441, and J449) to identify COPD. Kaplan-Meier analysis was used to compare 30-day all-cause mortality in COPD patients with and without 2-day AKI. A Cox proportional hazards model was employed to investigate risk factors associated with 30-day all-cause mortality in COPD patients. Results: This study included 2,609 patients with COPD, of whom 1,514 (58.03%) developed AKI within 2 days, while 1,095 (41.97%) did not. Patients with COPD, those who developed AKI within 2 days were older than those who did not develop AKI within 2 days [median: 72.7 (65.1, 80.0) Conclusions: The occurrence of 2-day AKI was an independent risk factor for 30-day all-cause mortality in patients with COPD. Clinically, these findings highlight the importance of providing early kidney protection for patients with COPD.