Comparison of the Effectiveness of Body Surface Area Estimation Formulas in Predicting the Risk of Death in Patients with Heart Failure.

Background/Objectives: Body surface area is one of the most important anthropometric parameters in medicine. The study's primary objective is to compare the consistency of the BSA estimation results through applying available formulas. Other objectives include determining the ability of these formulas to discriminate between death and survival in patients, comparing the formulas' diagnostic features, and investigating whether the risk associated with a low BSA is independent of BMI. Methods: This study included 1029 patients (median age, 54 years; female, 13.7%; NYHA I/II/III/IV, 6.3%/36.5%/47.7%/9.5%) diagnosed with heart failure. For each patient, BSA was calculated using 25 formulas. Over the 3-year observation period, 31.2% of the patients died. Results: The average BSA value of the optimal discrimination thresholds was 1.79 m² ± 0.084 m² and the BSA difference between the estimators with the lowest (BSA_Meeh1879) and the highest (BSA_Nwoye1989) optimal discrimination thresholds was 0.42 m². The lowest mortality rate was 35.2% and occurred in the subgroup of individuals with BSA values below the optimal discrimination threshold using the BSA_Schlich2010 estimator. The highest mortality was predicted when the estimator BSA_Meeh1879 or BSA_{Livingston&Lee2001} was used. Conclusions: Our study showed a relatively good concordance of 25 BSA estimators in BSA assessment in patients, without extremes of weight or height being known to disrupt it. All BSA estimators presented a significant, although weak, ability to discriminate death from survival at 3-year follow-up; however, BSA is not a very good predictor of HF mortality at 3 years. The higher risk of death in smaller patients, as shown by BSA, was independent of BMI in all but two BSA estimators.