Lower Drug Costs, Higher Utilization Observed in Diabetes Patients Enrolled in Medicaid

Due to concerns surrounding increased prices of antidiabetic medication for drug affordability in the United States, new research explored the experience of patients with diabetes among different types of insurance coverage.

Led by Peggah Khorrami, MPH, Department of Health Policy and Management, Harvard T. H. Chan School of Public Health, the team compared utilization patterns and costs of prescription drugs to treat diabetes in low-income patients with Medicaid versus those with Marketplace insurance.

“In this cross-sectional study, drug utilization across multiple drug classes was higher and drug costs were significantly lower for adults with diabetes enrolled in Medicaid than for those with subsidized Marketplace plans,” investigators wrote.

Methods

The study utilized data from the Colorado all payer claims database (APCD), which was merged with income data from the Medicaid and Marketplace program from 2014 and 2015.

Investigators limited the sample to adults aged 19 - 64 years with income between 75% and 200% of the federal poverty level (FPL). They noted that individuals with income between 75% - 138% of FPL are eligible for Medicaid, while those with higher incomes can purchase subsidized private insurance through the ACA Marketplace.

The primary outcomes were considered drug utilization (prescription drug fills) and drug costs (total costs and out-of-pocket costs). Then, secondary outcomes were months with an active prescription for noninsulin antidiabetic medication.

Utilization classified antidiabetic medication into 5 categories of noninsulin medication (dipeptidyl peptidase 4 [DPP-4] inhibitors, glucagon-like peptide 1 [GLP-1] agonists, sodium-glucose transport protein 2 [SGLT-2] inhibitors, sulfonylureas, and metformin) and 3 categories of insulin (basal, meal-time, and combination insulins).

In the study, an all-payer claims database was combined with income data and linear models were used to adjust for clinical and demographic confounders. Data analysis occurred from September 2020 - April 2021.

Findings

A total of 22,788 diabetic patients were included in the study, with 20,245 (88.8%) enrolled in Medicaid and 2543 (11.2%) eligible for a Marketplace plan. Those eligible for Marketplace were older (mean age, 52.12 years versus 47.70 years), while Medicaid-eligible individuals were more likely to be female (12,429, 61.4% versus 1412, 55.6%).

Data additionally show Medicaid-eligible individuals were significantly more likely to fill prescriptions for DPP-4 inhibitors (adjusted difference, -3.7%; 95% CI, -5.3 to -2.1, P <.001) and sulfonylurea (adjusted difference, -6.6%; 95% CI, -8.9 to -4.3; P <.001).

They observed overall rates of insulin use were similar in the 2 groups (adjusted difference, -2.3%; 95% CI, -5.1 to 0.5, P = .11), with basal insulin the most frequently used type.

In terms of costs of treatment, out-of-pocket costs for non insulin medications were 84.4% - 95.2% lower, while total costs were 9.4% to 54.2% lower in Medicaid than in Marketplace plans. Meanwhile, out-of-pocket costs for insulin were 76.7% - 94.7% lower in Medicaid than in Marketplace plans.

Further, the percentage of months of apparent medication coverage were shown to be similar between the groups for 4 of 5 drug classes examined. Marketplace-eligible patients had a greater percentage of months than Medicaid-eligible patients for sulfonylurea (adjusted difference, 5.3%; 95% CI< 0.3% - 10.4%, P = .04).

Takeaways

“Overall drug costs were substantially lower for non-insulin medications in Medicaid than in Marketplace insurance, whereas differences in insulin costs were variable,” investigators concluded.

The study, “Differences in Diabetic Prescription Drug Utilization and Costs Among Patients With Diabetes Enrolled in Colorado Marketplace and Medicaid Plans, 2014-2015,” was published in JAMA Network Open.