Semaglutide significantly reduces blood eosinophil levels in adults, with greater impact in non-obese individuals.

Glucagon-like peptide-1 receptor agonists (GLP-1RAs) like semaglutide are primarily used for glycemic control and weight management. However, emerging research suggests broader anti-inflammatory benefits, particularly in conditions involving eosinophilic inflammation such as asthma. Current treatments for eosinophilic diseases often have side effects or limited efficacy, prompting interest in novel therapeutic avenues. This study addresses the gap in understanding the direct impact of GLP-1RAs on blood eosinophil levels in a real-world setting.

Researchers conducted a retrospective, single-center study in Shanghai, China, involving 371 adult participants newly prescribed semaglutide. Data on demographic characteristics, complete blood counts (including blood eosinophil count, BEC, and eosinophil percentage), and lipid profiles were collected from electronic medical records before and after treatment. Subgroup analyses were performed based on a baseline BEC cut-off of 150/µL and a BMI threshold of 28 kg/m². Multiple linear regression analysis identified factors influencing eosinophil reduction.

Among 371 participants, blood eosinophil count (BEC) significantly decreased from a baseline of 160(150)/µL to 110(100)/µL after semaglutide treatment (P < 0.001). Eosinophil percentage also declined from 2.20(1.80)% to 1.60(1.40)% (P < 0.001). The proportion of individuals with BEC < 150/µL increased from 44.20% at baseline to 65.79% post-treatment. Eosinophil reduction was observed across all baseline eosinophil levels. Notably, the percentage reduction in eosinophil count was significantly greater in the BMI-low group compared to the BMI-high group.

The percentage reduction in eosinophil count was greater in the BMI-low group than in the BMI-high group (-31.58% vs. -21.04%, P = 0.037). Multiple linear regression identified baseline eosinophil count as the sole independent predictor of greater treatment-induced eosinophil reduction.