Prognostic value of first 24-hour urine output in patients with acute myocardial infarction in intensive care units: a retrospective study based on the MIMIC-IV database

Purpose: To investigate the effect of first 24-hour (24-h) urine output (UO) on in-hospital and 1-year mortality in patients admitted to intensive care units due to acute myocardial infarction. Methods: This was a retrospective cohort study based on the medical information mart for intensive care IV database involving patients admitted to intensive care units due to acute myocardial infarction. Patients were classified as low UO (LUO), high UO (HUO), and middle UO with a first 24-h UO below 800 ml, over 2500 ml, or in between, respectively. The primary outcome was in-hospital mortality and the secondary outcome was 1-year mortality. Results: A total of 4337 patients were involved. Taking middle UO group as reference, after adjusting for confounders including age, gender, height, weight, comorbidity, occurrence of cardiogenic shock, revascularization, blood pressure, creatinine, N-terminal pro-brain natriuretic peptide, and use of loop diuretics, LUO was independently associated with higher in-hospital mortality [odds ratio 4.05, 95% confidence interval (CI): 3.12-5.26], while HUO was an independent protective factor (odds ratio 0.52, 95% CI: 0.35-0.77). In the multivariant Cox regression model, LUO was an independent risk factor for 1-year mortality (hazard ratio 2.65, 95% CI: 2.16-3.26), while HUO did not show significant association. Conclusion: In patients admitted to intensive care units due to acute myocardial infarction, first 24-h UO <800 ml was a strong predictor for higher in-hospital and 1-year mortality, while first 24-h UO over 2500 ml was associated with lower in-hospital mortality but not long-term mortality.