Systemic Laboratory Alterations Associated With Heart Failure in Severe Mitral Regurgitation: A Retrospective Observational Study

Background: The systemic laboratory abnormalities accompanying documented heart failure in patients hospitalized with severe mitral regurgitation (MR) have not been fully characterized across multiple biological domains within the same cohort.Methodology: In this retrospective, single-center, cross-sectional study, 107 adults with echocardiographically documented severe MR were compared according to the presence (n = 49) or absence (n = 58) of a heart failure diagnosis at discharge.Inflammatory, hematological, renal, electrolyte, hepatic, and coagulation measures were evaluated using multiplicity-adjusted comparisons and age-and sexadjusted domain-specific logistic regression.A post hoc model integrating age, sex, C-reactive protein, anemia, and estimated glomerular filtration rate (eGFR) <60 mL/min/1.73m² was explored using sensitivity analyses and fixed-model bootstrap validation.Results: Multiple laboratory domains differed by heart failure status.In the post hoc integrated model, eGFR < 60 mL/min/1.73m² showed the most consistent association with concomitant heart failure (odds ratio, 5.56; 95% confidence interval, 1.94-15.94;P = 0.001); C-reactive protein and anemia were not statistically significant after mutual adjustment.The apparent and optimism-corrected areas under the curve were 0.809 and 0.780, respectively; corresponding Brier scores were 0.175 and 0.196.Conclusions: Among hospitalized patients with severe MR, documented concomitant heart failure was accompanied by abnormalities across several laboratory domains, with reduced renal function showing the most consistent association in exploratory multivariable analyses.The retrospective design, dischargediagnosis-based heart failure classification, incomplete echocardiographic characterization, and limited sample size preclude causal or predictive interpretations.