Prescription Copayment Associated with GLP-1 RA, SGLT2i Therapy Adherence

Utibe R. Essien, MD, MPH

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New research indicates prescription copayments were independently associated with 12-month adherence to glucagon-like peptide-1 receptor agonist (GLP-1 RA) and sodium-glucose co-transporter 2 inhibitor (SGLT2i) medications in patients with type 2 diabetes (T2D) and heart failure.¹

Thus, the findings suggest individuals with a lower medication copayment had significantly higher odds of 12-month adherence to GLP-1 RA and SGLT2i therapies, compared with individuals with a higher copayment.

“These differences persisted even when controlling for patient demographics, clinical, and socioeconomic covariates, demonstrating an independent association of copayment amount with adherence to these therapies,” wrote the investigative team, led by Utibe R. Essien, MD, MPH, from the division of general internal medicine and health services research at the David Geffen School of Medicine at the University of California, Los Angeles.

The United States is experiencing a steady rise in the prevalence of T2D and heart failure, making modifiable risk factor control, including physical activity and diet, critical to managing these diseases. But, the prevention of chronic complications additionally requires effective adherence to prescription medications proven to improve outcomes, including GLP-1 RAs and SGLT2is. Evidence has shown these medications to have a significant reduction in morbidity and mortality for patients with T2D and heart failure and contemporary guidelines have been updated to decrease adverse event risk in these patients.

However, even with their proven benefit, high out-of-pocket costs can be a significant barrier to medication initiation and there is a paucity of data on how prescription copayment may influence the long-term adherence to these medications.² As a result, Essien and colleagues analyzed the association of prescription copayment with adherence to GLP-1RA and SGLT2i therapies in a nationwide cohort of individuals with T2D and/or heart failure over 12 months.

The retrospective cohort study used deidentified data from Optum Insight’s Clinformatics Data Mart Database of over 68 million enrollees with commercial and Medicare health insurance plans. Using the pharmacy claims data, investigators identified all individuals with a new prescription, defined as having no record of a GLP-1 RA or SGLT2i prescription fill in the previous 6 months from January 2014 to September 2020. The primary outcome was 12-month adherence to GLP-1 RA or SGLT2i therapies, defined as a proportion of days covered (PDC) of 80% or greater at 1 year.

For the analysis, the independent variable of interest was a 30-day prescription copayment, obtain from pharmacy claims and defined as the individual-level median over 12 months. Investigators categorized copayment as low (<$10), medium ($10 to <$50), or high (≥$50) based on the distribution of copayment data. Multivariable logistic regression models were used to examine the association between copayment category and 1-year adherence, adjusting for demographics, medical comorbidities, and socioeconomic factors.

The final study cohort included 94,610 individuals who initiated GLP-1 RA or SGLT2i therapy during the study period, including 43,384 (45.9%) female individuals with an overall mean age of 61.8 years. A total of 39,149 individuals had a claim for a GLP-1 RA, of which 25,557 individuals (65.3%) achieved a PDC of ≥80% at 12 months.

Within the fully multivariable-adjusted model, participants with a medium (adjusted odds ratio [aOR], 0.62; 95% CI, 0.58 - 0.67) or high (aOR, 0.47; 95% CI, 0.44 - 0.51) copayment were significantly less likely to have 12-month adherence to GLP-1 RA therapies, compared with those with a low copayment.

Meanwhile, the final cohort included 51,072 individuals with a pharmacy claim for an SGLT2i medication, of which 37,339 (73.1%) individuals achieved 12-month adherence (PDC ≥80%) for SGLT2i use. In the multivariable-adjusted model, those with a medium (aOR, 0.67; 95% CI, 0.63 - 0.72) or high (aOR, 0.68; 95% CI, 0.63 - 0.72) copayment were significantly less likely to have 12-month adherence to SGLT2i therapies, compared with those with a low copayment.

Essien and colleagues indicated these findings in a commercially insured cohort may have important implications for ensuring equitable access to medical management of chronic cardiometabolic diseases.

“Lowering high out-of-pocket prescription costs may be key to improving adherence to guideline-recommended therapies and advancing the overall quality of care in T2D and heart failure management,” investigators wrote.

References

1. Essien UR, Singh B, Swabe G, et al. Association of Prescription Co-payment With Adherence to Glucagon-Like Peptide-1 Receptor Agonist and Sodium-Glucose Cotransporter-2 Inhibitor Therapies in Patients With Heart Failure and Diabetes. JAMA Netw Open. 2023;6(6):e2316290. doi:10.1001/jamanetworkopen.2023.16290
2. EberlyLA,YangL,EssienUR,etal.Racial,ethnic,andsocioeconomicinequitiesinglucagon-likepeptide-1 receptor agonist use among patients with diabetes in the US. JAMA Health Forum. 2021;2(12):e214182-e214182. doi:10.1001/jamahealthforum.2021.4182