Cost-Sharing Caps on Insulin Medication Could Cut Costs for Diabetics

Kao-Ping Chua, MD, PhD

While cost-sharing caps may help improve the overall costs of medications such as insulin, new research suggests additional policy changes are needed if officials hope to address those who face the greatest hurdles in affording their medications.

Results of the study indicate cost-sharing caps improved the affordability of insulin among children and young adults with type 1 diabetes, but results also suggest the benefit of such a policy varies depending on the cap itself and the type of insurance.

“Cost-sharing caps don’t help the uninsured and don’t address the underlying problem of high insulin prices”, says lead author Kao-Ping Chua, MD, PhD, a researcher and pediatrician at C.S. Mott Children’s Hospital and the University of Michigan Medical School’s Susan B. Meister Child Health Evaluation and Research Center, in a statement. “However, our study shows that caps could be a useful stop-gap measure to improve insulin affordability until more comprehensive reforms are implemented.”

To develop a greater understanding of how cost-sharing caps might impact out-of-pocket costs and affordability of insulin, Chua and a team of investigators conducted a cross-sectional analysis of information from the 2018 IBM MarketScan Commercial Database. The specific aim of the analysis was to estimate the potential change in insulin out-of-pocket spending among privately insured individuals 21 years of age and younger if national $25 and $100 caps were implemented.

For inclusion in the study, patients need to be between 1-21 years of age with continuous enrollment during the 2018 calendar year. Patients were also required to have 1 or more type 1 diabetes codes in 2017 and 1 or more insulin pharmacy claims during 2018.

For the $25 cap, investigators restricted out-of-pocket spending for insulin prescriptions to $25 if supplied for 30 days or less, $50 if supplied for 31-60 days, $75 if supplied for 61-90 days, and so on. For the $100 cap, the corresponding caps were $100 for 30 days or less, $200 for 31-60 days, and so on.

In total, 12,185 patients were identified for inclusion in the analysis, of which 3116 were enrolled in high deductible health plans. Of the 12,185, 2088 were between the ages of 1-11 years, 5054 were between 12-17 years of age, and the remaining 5043 were aged 18-21 years. Additionally, the mean number of annual insulin claims among subjects was 7.7 (SD, 4.8) and mean days supplied per claim was 49.3 (SD, 28.4).

The mean annual out-of-pocket spending for these patients was $494 (SD, 640) while the median figure was $308 (25th-75th percentile, $120-638). For 1538 patients, annual out-of-pocket spending exceed $1000.

Investigators estimated a $25 cap would benefit 7302 (59.9%) patients. Among patients who would benefit from this cap, mean annual out-of-pocket spending would decrease from $741 to $261. In comparison, a $100 cap would benefit 2151 patients. Among these patients, mean annual out-of-pocket spending would decrease from $1343 to $786.

In patients enrolled in high deductible health plans, mean annual out-of-pocket spending was $643 (SD, 741) and the mean figure was $428 (25th-75th percentile, 102-917). Among the 3116 in this group, 677 had annual out-of-pocket spending exceeding $1000. Investigators estimated a $25 cap would benefit 2277 (73.1%) of patients.

Among these patients, mean annual out of pocket spending would decrease by $628, which is greater than the mean decrease seen among those not enrolled in high deductible health plans. Similarly, investigators estimated a $100 cap would benefit a greater proportion of high deductible health plan enrollees than nonenrollees (31.9% vs 12.8%; P <.001).

This study, “Potential Change in Insulin Out-of-Pocket Spending Under Cost-Sharing Caps Among Pediatric Patients With Type 1 Diabetes,” was published in JAMA Pediatrics.