ABSI (A Body Shape Index) and ARI (Anthropometric Risk Indicator) in Bariatric Surgery. First Application on a Bariatric Cohort and Possible Clinical Use.

Background: BMI (body mass index) is used to identify candidates for bariatric surgery, with a criterion of BMI ≥ 40. For lesser degrees of obesity, BMI 35-39.9, comorbidities are also considered. A Body Shape Index (ABSI) was derived to correct WC (waist circumference) for BMI and height. ABSI has been shown to be a linear predictor of long-term mortality across the range of BMI. Anthropometric risk indicator (ARI) combines the complementary contributions of BMI and ABSI and further improves mortality hazard prediction. We report for the first time ABSI and ARI for a bariatric surgical cohort at baseline and with 3-year follow-up.

Methods: ABSI and BMI were calculated for 101 subjects from our bariatric surgery center database at baseline and after 3 years of follow-up. Raw values for BMI and ABSI were converted to Z scores and ARI values based on sex- and age-specific normals and risk associations from the National Health and Nutrition Examination Survey (NHANES) III sample of the US general population.

Results: Baseline scores for the anthropometric variables BMI and ABSI and the corresponding ARI were all higher than for the NHANES population sample. At 3-year post surgery, all three measures decreased significantly. While baseline BMI did not predict the change in mortality risk by ARI, baseline ABSI did (r = - 0.73), as did baseline ARI (r = - 0.94).

Conclusion: Sleeve gastrectomy lowers ABSI and the associated mortality risk estimated from population studies after 3 years of follow-up. Considering our results, bariatric surgical candidates with BMI in the range of 35 to 39.9 with an increased ABSI-related mortality risk may have considerable survival benefit from bariatric surgery, even in the absence of qualifying comorbidities.

Trial Registration Number: 2814.