Approximately two thirds of patients with obesity respond to glucagon-like peptide-1 receptor agonists (GLP-1 RA) with ≥ 5% weight loss. Predictive markers of weight loss efficacy are needed. In a population-based cohort, the Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) index and fasting insulin level positively correlate with ten-year weight gain. This study aims to to assess if HOMA-IR index can be used as a predictive marker of weight loss response to GLP-1 RAs in clinical practice.


We studied 62 patients with obesity and without diabetes who were seen at least twice in the Penn Metabolic Medicine Clinic between July 2017 to March 2019, and had fasting insulin and glucose levels obtained prior to GLP-1 RA initiation. We assessed the relationship between HOMA-IR index and percent weight loss during GLP-1 RA treatment, as well as average weight loss in all subjects treated with GLP-1 RAs.


Of the 62 patients, 79.03% lost greater than 5% of their weight. The average weight loss was 9.86 ± 5.84%. For all participants, the difference in weight between initial weight and lowest weight during treatment was statistically significant (p < 0.001). The relationship between HOMA-IR index and percent weight loss was not statistically significant (p = 0.59).


In routine clinical practice, GLP-1 RA therapy can provide patients with significant weight loss regardless of insulin resistance status as assessed by HOMA-IR.