Correlation between urea-to-creatinine ratio and poor prognosis of intensive care unit patients with chronic obstructive pulmonary disease: a study based on the MIMIC-IV database.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is a leading cause of mortality worldwide. ICU patients with COPD are facing particularly poor outcomes. Existing biomarkers like blood urea nitrogen (BUN) have shown inconsistent prognostic value. Recent evidence suggests the urea-to-creatinine ratio (UCR) may better reflect muscle catabolism and systemic dysfunction in critical illness. However, its clinical role in predicting prognosis for COPD patients needs to be confirmed. This study aimed to investigate the correlation between UCR levels and poor prognosis in ICU patients with COPD. METHODS: The clinical data of 2,305 COPD patients were retrieved from the database of Medical Information Mart for Intensive Care IV (MIMIC-IV), including demographic information, vital signs upon ICU admission, comorbidities, laboratory test indicators, arterial blood gas analysis results, and disease severity scores. Patients were grouped into U1 group (UCR < 15.71, n = 558), U2 group (15.71 ≤ UCR < 20.57, n = 593), U3 group (20.57 ≤ UCR < 27.575, n = 578), and U4 group (UCR ≥ 27.575, n = 576) based on the quartile levels of UCR measured at ICU admission. The primary endpoint was 90-day mortality. Clinical baseline characteristics and prognostic endpoints were compared across groups. Logistic regression analysis and restricted cubic spline (RCS) analysis were employed to evaluate the correlation between different UCR levels and the poor prognosis of COPD patients. RESULTS: Patients in the higher UCR groups showed an increased rate of mechanical ventilation and significantly higher mortality rates within the ICU, at 28 days, 30 days, and 90 days (all p < 0.001). A logistic regression model, constructed using important feature variables selected by random forest, revealed that patients in the highest UCR quartile (U4 group) had a significantly elevated mortality risk (OR = 1.835, 95% CI: 1.37 ~ 2.458, p < 0.01). RCS analysis demonstrated a linear correlation between UCR levels and both patient mortality risk and the rate of mechanical ventilation. CONCLUSION: High UCR is correlated with poor prognosis of patients with COPD.

Pubmed ID: 42157169