Association of the serum uric acid to high-density lipoprotein cholesterol ratio with in-hospital mortality in patients with acute kidney injury: a retrospective cohort study.

Background: Acute kidney injury (AKI) has a high in-hospital mortality rate, requiring better prognostic tools. The uric acid to HDL cholesterol ratio (UHR), a novel biomarker of metabolic inflammation, was investigated for predicting mortality in AKI patients. Methods: A retrospective cohort study was conducted from January 2021 to January 2024, including 500 adult AKI patients diagnosed according to KDIGO criteria. Patients with chronic kidney disease requiring dialysis, those transferred to other facilities, and those with incomplete medical records were excluded. Data on demographics, comorbidities, vital signs, laboratory tests, and clinical outcomes were extracted from electronic medical records. The primary outcome was all-cause in-hospital mortality. Results: The study enrolled 435 survivors and 65 non-survivors. Non-survivors were older and had a higher prevalence of hypertension and diabetes, with more severe renal impairment and inflammation, indicated by higher serum creatinine, blood urea nitrogen, and C-reactive protein levels. The univariate analysis revealed significant associations between in-hospital mortality and several variables, including UHR, age, serum creatinine, blood urea nitrogen, urine output, C-reactive protein, and estimated glomerular filtration rate. In multivariate analyses, with each unit increase in UHR associated with a 55% higher hazard of in-hospital mortality after adjustment (HR: 1.55; 95% CI: 1.18-2.01, p=0.002). The association was particularly stronger in older patients, those with higher serum creatinine, elevated CRP levels, and lower urine output. Conclusions: UHR independently predicts in-hospital mortality in AKI, supporting its use for risk stratification, though further mechanistic studies are needed.