C-index predicts adverse outcomes, death in anticoagulated patients with AF

The conicity index (C-index) appears to be the most robust and most consistent prognostic value among adiposity indices in anticoagulated patients with atrial fibrillation (AF), suggests a study.

“Its integration into conventional risk scores may enhance risk stratification in this high-risk population,” the researchers said.

A total of 2,080 AF outpatients (mean age 77 years, 52.8 percent female) initiating oral anticoagulation between January 2016 and November 2021 were enrolled in this prospective study. The researchers evaluated BMI, C-index, weight-adjusted waist index, waist-to-height ratio, body roundness index, and a body shape index.

The primary outcomes included thromboembolic events, major bleeding (MB)/clinically relevant non-MB (CRNMB), and major adverse cardiovascular events (MACE), while secondary outcomes included all-cause and cardiovascular death. Associations with clinical outcomes were assessed using restricted cubic spline (RCS), Cox models, and receiver operating characteristic analyses.

Of the patients, 18.1 percent experienced a thromboembolic event, 13.5 percent had MB/CRNMB, and 11.3 percent suffered a MACE during 1.8 years of follow-up. In RCS analysis, all adiposity indices correlated with adverse outcomes, but only the C-index showed a nonlinear relationship.

Multivariate analysis revealed that only high C-index showed an independent association with thromboembolic events (adjusted hazard ratio [aHR], 2.29, 95 percent confidence interval [CI], 1.58‒3.34), MB/CRNMB (aHR, 2.10, 95 percent CI, 1.58‒2.79), and MACE (aHR, 2.48, 95 percent CI, 1.79‒3.43) compared with low C-index. A high C-index was also predictive of cardiovascular and all-cause mortality.

“The C-index consistently showed the highest discriminative performance for all primary outcomes, which further improved when integrated with CHA₂DS₂-VASc and HAS-BLED,” the researchers said.