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Lowering Cardiometabolic Drug Costs May Improve Diabetes Health Outcomes


Patients enrolled in a preventive drug list (PDL) benefit saw an 8.4% reduction in acute, preventable diabetes complication days, and PDL members residing in lower-income areas saw a 10.2% decrease compared with control members.

Lowering out-of-pocket (OOP) expenses for cardiometabolic medications could potentially lead to slight enhancements in near-term health results for commercially insured individuals with diabetes, according to a new study published in JAMA Health Forum.

PDLs were linked to improved diabetes outcomes | Image credit: Cagkan – stock.adobe.com

PDLs were linked to improved diabetes outcomes | Image credit: Cagkan – stock.adobe.com

Type 2 diabetes has seen a rise in prevalence over the past 2 decades, with pharmacotherapy playing a crucial role in managing complications. As acute and chronic diabetes complications increase, particularly among younger and socioeconomically disadvantaged populations, OOP costs remain a barrier to accessing essential medications. Employers have responded by adopting preventive drug lists (PDLs), which offer reduced OOP expenses for preventive medications, including those for diabetes. While prior research suggests increased medication fills with PDL adoption, its impact on health outcomes remains underexplored, especially for individuals with lower incomes.

The cohort study investigated the impact of a PDL value-based medication benefit on diabetes health outcomes. Specifically, there was an 8.4% reduction in acute, preventable diabetes complication days observed in the entire PDL group, as well as a 10.2% decrease among PDL members residing in lower-income areas. These findings are in comparison to matched control group members whose cardiometabolic medications continued to be subject to deductibles or copayments during the follow-up period.

The study was conducted using data from a large, national commercial health plan spanning from January 2004 to June 2017, focusing on patients aged 12 to 64 years with diabetes. Participants enrolled through employers adopting PDLs experienced reduced OOP costs for common cardiometabolic drugs, leading to increased usage and coverage of antidiabetic agents.

Among the 10,588 patients in the intervention group and 690,075 patients in the control group after matching and weighting, significant improvements were observed. From baseline to follow-up, the proportion of days covered by noninsulin antidiabetic agents increased by 4.7% (95% CI, 3.2%-6.2%) in the PDL group and by 7.3% (95% CI, 5.1%-9.5%) among PDL members from lower-income areas compared with controls. Higher usage of noninsulin antidiabetic agents also saw a substantial increase, rising by 11.3% (95% CI, 8.2%-14.5%) in the PDL group and by 15.2% (95% CI, 10.6%-19.8%) among members from lower-income areas compared with controls.

The PDL group also experienced an 8.4% relative reduction in complication days (95% CI, −13.9% to −2.8%) with an absolute reduction of −20.2 (95% CI, −34.3 to −6.2) per 1000 members per year compared with controls from baseline to follow-up. PDL members residing in lower-income areas had a similar relative reduction of 10.2% (95% CI, −17.4% to −3.0%) with an absolute reduction of −26.1 (95% CI, −45.8 to −6.5) per 1000 members per year.

According to the authors, these findings suggest that targeted cost-sharing reductions could play a crucial role in improving health outcomes for commercially insured patients with diabetes, especially those with lower incomes.

“Although we found that residents of lower-income areas with PDLs had a larger magnitude of reduction than counterparts residing in higher-income areas, effect estimates did not differ statistically,” the authors said. “Nevertheless, our results suggest that targeting out-of-pocket cost reductions to specific populations, in this case patients with diabetes from lower-income areas, might enhance health outcomes. Preventive drug lists might also benefit patients with other chronic illnesses at risk for treatment adherence–related complications, but further research is needed.”

Among the limitations of this study, the findings are applicable only to patients with diabetes enrolled in commercial health plans, limiting generalizability. Additionally, the assignment to PDL coverage was not random but rather determined by specific employers, potentially introducing selection bias. Although efforts were made to minimize this bias through matching and weighting, there may still be residual confounding. Further, the study relied on claims-based algorithms to identify PDL exposure, which may have introduced errors in group assignment. While the analyses suggest reliable identification of PDL adoption, the study's reliance on 1-year continuous enrollment could affect generalizability and bias results toward the null, and its focus on short-term outcomes necessitates longer-term studies with larger samples to comprehensively assess the impact of PDL enrollment on clinical outcomes.


Wharam JF, Argetsinger S, Lakoma M, Zhang F, Ross-Degnan D. Acute diabetes complications after transition to a value-based medication benefit. JAMA Health Forum. 2024;5(2):e235309. doi:10.1001/jamahealthforum.2023.5309

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