Prophylactic heparin and mortality in patients with acute respiratory failure in the ICU: A retrospective cohort study based on the MIMIC-IV database.

This study evaluates the association between prophylactic heparin use and mortality in intensive care unit (ICU) patients with acute respiratory failure (ARF). A retrospective cohort study was conducted using the Medical Information Mart for Intensive Care IV database. Adult ICU patients diagnosed with ARF were included. Patients receiving subcutaneous unfractionated heparin (5000 units) within 72 hours of ICU admission were compared with non-recipients. Propensity score matching was used to balance baseline characteristics. The primary outcome was 28-day all-cause mortality; secondary outcomes included in-hospital mortality and length of stay. Of 880 eligible patients, 703 received heparin and 177 did not. After 1:1 propensity score matching, 256 patients were analyzed (128 per group). Heparin use was associated with significantly lower 28-day all-cause mortality (32.03% vs 52.34%, P = .002) and in-hospital mortality (28.12% vs 46.88%, P = .003). Multivariable Cox regression confirmed reduced mortality risks (28-day hazard ratio = 0.46, 95% confidence interval: 0.30-0.69; in-hospital hazard ratio = 0.45, 95% confidence interval: 0.29-0.70). Subgroup analyses consistently supported these findings. However, heparin use was associated with longer ICU and hospital length of stay. Early prophylactic heparin administration is independently associated with reduced short-term mortality in ICU patients with ARF, supporting its potential role in comprehensive ARF management.