https://www.ahajournals.org/doi/10.1161/CIRCIMAGING.125.019491Alternative methods for indexing left atrial volume (LAV) have been proposed to improve proportional cardiac scaling in individuals with overweight or obesity. However, evidence supporting superior prognostic performance compared with standard body surface area (BSA) indexation remains limited. A registry-based analysis published in Circulation: Cardiovascular Imaging compared multiple LAV indexation methods for prediction of all-cause mortality in patients with overweight or obesity.

The study used data from the National Echocardiography Database Australia linked to mortality outcomes. Individuals with body mass index (BMI) ≥25 kg/m² and valid measurements of LAV, height, weight, and left ventricular ejection fraction were included. Receiver operating characteristic analyses were performed to compare 9 LAV indexation methods. The analysis included 109,543 individuals with a mean age of 60±16 years; 47% were women.

Findings

• Most LAV indexation methods showed similar prognostic performance for all-cause mortality, with area under the curve values ranging from 0.60 to 0.62.
• Unindexed LAV and LAV indexed to BMI demonstrated the lowest predictive performance, with area under the curve values of 0.600 (95% confidence interval [CI] 0.595-0.604) and 0.602 (95% CI 0.597-0.606), respectively.
• Prognostic performance remained consistent across age groups, sex categories, and follow-up durations.
• A mortality threshold for LAV indexed to BSA was identified at 34 mL/m², without significant sex-related differences.

Most LAV indexation methods performed similarly for mortality prediction in patients with overweight or obesity. The findings support continued use of standard LAV indexed to BSA, including the current normal reference threshold of <34 mL/m².