Association of Patient Cost-Sharing With Adherence to GLP-1a and Adverse Health Outcomes

OBJECTIVE To examine the associations between patient out-of-pocket (OOP) costs and nonadherence to glucagon-like peptide 1 receptor agonists (GLP-1a), and the consequent impact on adverse outcomes, including hospitalizations and emergency department (ED) visits. RESEARCH DESIGN AND METHODS This retrospective cohort study used MarketScan Commercial data (2016–2021). The cohort included nonpregnant adults aged 18–64 years with type 2 diabetes who initiated GLP-1a therapy. Participants were continuously enrolled in the same private insurance plan for 6 months before the prescription date and 1 year thereafter. Exposures included average first 30-day OOP costs for GLP-1a, categorized into quartiles (lowest [Q1] to highest [Q4]). Primary outcomes were the annual proportion of days covered (PDC) for GLP-1a and nonadherence, defined as PDC <0.8. Secondary outcomes included diabetes-related and all-cause hospitalizations and ED visits 1 year post-GLP-1a initiation. RESULTS Among 61,907 adults who initiated GLP-1a, higher 30-day OOP costs were associated with decreased adherence. Patients in the highest OOP cost quartile (Q4: $80–$3,375) had significantly higher odds of nonadherence (odds ratio [OR]1.25; 95% CI 1.19–1.31) compared with those in Q1 ($0–$21). Nonadherence was linked to increased incidence rates of diabetes-related hospitalizations or ED visits (incidence rate ratio [IRR] 1.86; 95% CI 1.43–2.42), cumulative length of hospitalization (IRR 1.56; 95% CI 1.41–1.72), all-cause ED visits (IRR 1.38; 95% CI 1.32–1.45), and increased ED-related costs ($69.81, 95% CI $53.54–$86.08). CONCLUSIONS Higher OOP costs for GLP-1a were associated with reduced adherence and increased rates of adverse outcomes among type 2 diabetes patients.