The Association of Renin-Angiotensin System Blockades and Mortality in Patients with Acute Exacerbation of Chronic Obstructive Pulmonary Disease and Acute Respiratory Failure: A Retrospective Cohort Study.

Background: Acute respiratory failure (ARF) is a common cause of admission to the intensive care unit (ICU) for patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD). There is still a lack of effective interventions and treatments. ACE inhibitors (ACEI)/ angiotensin II receptor blockers (ARB) were effective in COPD patients. We aimed to study the effect of ACEI/ARB use on AECOPD combined with ARF and evaluate the effect of in-hospital continuation of medication. Methods: We included patients with AECOPD and ARF from the Medical Information Bank for Intensive Care (MIMIC-III) database. MIMIC III is a large cohort database from Boston, USA. Patients were divided into two groups according to the use of ACEI/ARB before admission. Propensity score matching (PSM) was used to reduce potential bias between the two groups. Cox regression and Kaplan-Meier curves compared 30-day mortality in ACEI/ARB users and non-users. We also defined and analyzed the use of in-hospital ACEI/ARB. Multiple models were used to ensure the robustness of the findings. Subgroup analysis was used to analyze the variability between groups. Results: A total of 544 patients were included in the original study. After PSM, 256 patients were included in the matched cohort. Multivariate Cox regression showed 30-day mortality was significantly lower in ACEI/ARB users compared with controls (HR = 0.50, 95% CI: 0.29-0.86, Conclusion: This study found that pre-hospital ACEI/ARB use was associated with reduced mortality in patients with AECOPD and ARF.