Prognostic utility of the <scp>MECKI</scp> score in a mixed United States cohort

The Metabolic Exercise test data combined with Cardiac and Kidney Indexes (MECKI) score has demonstrated prognostic utility in European and Asian cohorts with heart failure with reduced ejection fraction (HFrEF). We sought to evaluate its performance in an American cohort. We retrospectively identified patients who underwent cardiopulmonary exercise testing (CPX) at our institution in 2022-2024 with data to calculate the MECKI and CPX Risk scores. The primary endpoint was a composite of death, heart failure admission, heart transplantation, or ventricular assist device. Survival analysis was assessed via Kaplan-Meier curves and log-rank test, with ROC curves for comparison. Overall, 803 patients met criteria, with 451 (56%) female, 228 (28%) Black race, and median body mass index 29.4 (25.0-34.2) kg/m². Pre-existing HFrEF was present in 187 (23%) patients. 719 (90%), 41 (5%), and 43 (5%) patients achieved MECKI scores <10%, 10%-20%, and ≥20%, respectively, with stepwise increases in 2-year risk of primary endpoints (log-rank χ² = 196.0, p < 0.001). ROC curves demonstrated better performance of MECKI scores compared to CPX Risk scores. Events were similarly predicted in patients with HFrEF, with similar performances between the two scores. In conclusion, in a mixed American cohort the MECKI score demonstrated robust performance in predicting event-free survival.