Factors associated with in-hospital mortality in patients with heart failure hospitalized for acute renal failure

Background: Acute renal failure (ARF) is a common complication in patients with heart failure (HF) and is associated with increased in-hospital mortality. Purpose: To determine the factors associated with mortality 14 days after hospital admission in patients with HF admitted for ARF. Methodology: Analytical cross-sectional study based on 1611 patients with chronic HF admitted for ARF. Biochemical and hemodynamic parameters were analyzed using Mann-Whitney U tests, Odds Ratio, prevalence ratio, Poisson regression, and binary logistics. A decision tree was used using a chi-squared automatic interaction detector (CHAID) to identify predictors of mortality. Results: The CHAID analysis identified five variables associated with 14-day mortality in patients with HF and ARF: white blood cell count (WBC), respiratory rate, sodium, diastolic blood pressure (DBP), and oxygen saturation (SpO₂ ). The terminal node with the highest association with mortality was comprised of patients with SpO₂ ≤ 93 % and WBC>17,000 mm³, presenting an adjusted odds ratio (aOR) of 2.62 (95 %CI:2.21-2.76) and an adjusted prevalence ratio (aPR) of 1.91 (95 %CI:1.41-1.98). This node showed a specificity of 98 % and a negative predictive value of 92 %. Patients in this group presented significantly higher values of anion gap, BUN, pulse and respiratory rate, and lower values of bicarbonate, DBP and SpO₂ . Conclusions: In patients with HF hospitalized for ARF, the coexistence of moderate hypoxemia and marked leukocytosis was associated with a higher risk of early mortality. Its identification and monitoring may be key to the implementation of therapeutic strategies.