B-140 Use of the metabolic health index for correlation with comorbidity reduction for patients undergoing bariatric surgery
Authors: Aravamudhan A , Ikramuddin S , Killeen A 
Published: October 2024

Abstract

Background
Bariatric surgery is a commonly performed procedure aimed at addressing obesity and its associated health issues. However, while weight loss is often a primary focus, the broader improvements in metabolic health, including reductions in conditions such as type 2 diabetes mellitus (T2DM) and dyslipidemia, are not consistently quantified. The recent development of the Metabolic Health Index (MHI) by van Loon et al. provides a potential laboratory index that encompasses various metabolic parameters to predict improvements in comorbidities post-surgery. Our study aimed to assess the utility of MHI in correlating with changes in metabolic health status among patients undergoing bariatric surgery at a U.S. medical center.

Methods
In our current study, we conducted a retrospective analysis of 300 patients who had undergone bariatric surgery between 2012 and 2019 at the University of Minnesota. We selected patients who had both baseline and one-year post-surgery laboratory values available, including age, hemoglobin A1C (HbA1c), triglycerides, potassium, and creatinine for estimated glomerular filtration rate (eGFR), which were necessary for calculating MHI using the equation of van Loon et al. Thirty patients met the inclusion criteria and their eGFRs were calculated using the 2021 CKD-EPI equation. Using the published formulae, we calculated the MHI for each patient before and after surgery. Patients were stratified based on improvements in diabetic (T2DM) and dyslipidemic status, with lower stratification numbers indicating better outcomes. We then conducted correlation analyses to examine the relationship between changes in MHI, individual components of MHI, BMI, and the reduction in the two comorbidities. We also examined if any of the initial values of MHI, its components and BMI correlated with the magnitude of reduction in the two comorbidities.

Results
In the patient cohort examined, initially 46.7% of the population were non-diabetic and this changed to 53.3% one year after surgery. The number of patients with diabetes decreased from 33.3% to 13.3%, indicating a benefit of bariatric surgery in alleviating type 2 diabetes mellitus (T2DM). Dyslipidemia decreased from 36.7% to 13.3% post-surgery. Most of the patients had reductions in both the BMI and MHI scales and a linear relationship between the two values was observed. A Spearman correlation analysis revealed that the values of HbA1c (rho= 0.56, p = 0.0014)) and MHI (rho = 0.5, p = 0.005) had a correlation with the reduction in T2DM and the reduction in triglycerides (rho= 0.73, p= 0.0) correlated with reduction in dyslipidemia. On the other hand, the reduction in BMI did not correlate with the improvement in the comorbidities examined. It was determined that the initial values of MHI, its components, and BMI had no correlation to the degree of reduction in comorbidities.

Conclusions
Our findings suggest that MHI and HbA1C may serve as valuable indicators of metabolic health improvements following bariatric surgery, while BMI changes alone may not fully capture these improvements. Laboratory-based measurements such as MHI offer a promising approach for assessing and monitoring metabolic health outcomes in bariatric surgery patients, providing insights beyond traditional weight-based metrics.