Association Between Medicare Drug Plan Ratings and Coverage Barriers for Non-Generic, Evidence-Based Cardiovascular Medications

RESEARCH LETTER

Direct oral anticoagulants (DOAC), sodium glucose cotransporter 2 inhibitors (SGLT2i), and angiotensin receptor neprilysin inhibitors (ARNI) are guideline-recommended medications for patients with common cardiovascular conditions. Many patients have limited access to these medications due to insurance barriers, including prior authorization, step therapy, and tier ≥3 cost sharing (leading to higher out-of-pocket costs).¹

Patients can obtain Medicare drug coverage through Medicare Advantage Plans (MA) or standalone Part D Prescription Drug Plans (PDP). Medicare drug coverage plans are graded on a 5-Star Rating system, and Medicare beneficiaries often choose higher rated plans.² Patients selecting higher rated plans may expect improved access to medications. However, Star ratings are primarily based on multiple non-medication access factors, including customer experience, quality of care metrics, and plan duration, and their association with medication access is unknown. This study aims to assess the association between Medicare Plan Star Rating and drug coverage barriers for three commonly used, non-generic, evidence-based cardiovascular medication classes: DOAC, SGLT2i, and ARNI.

This cross-sectional, plan-level analysis used the June 2023 Medicare Prescription Drug Plan Formulary, Pharmacy Network, Pricing Information and Summary Star Review files. All MA and PDP with available Star Rating and formulary data were included. Star Rating was categorized as Low (<3.5), High (3.5–4), and Highest (4.5–5).³

Specific medications for analysis were chosen based on high overall cost burden to Medicare (DOAC - apixaban or rivaroxaban, SGLT2i - empagliflozin or dapagliflozin, and ARNI - sacubitril-valsartan).⁴ The primary outcome was the presence of any of the following coverage barriers: prior authorization, step therapy, tier ≥3 cost sharing, or no coverage.¹ For classes with two drugs (DOAC and SGLT2i), coverage barriers had to exist for both medications to be counted. The secondary outcome was estimated 30-day out-of-pocket cost, calculated using copayment, co-insurance, and drug pricing information (deductible and insurance phase were not used for calculations). Associations between Star Rating category and outcomes were assessed with Chi-squared and Kruskal Wallis tests, (RStudio-2025.05.1). P-value ≤0.05 indicated statistical significance. MA and PDP were assessed in separate analyses. IRB approval was not required as criteria for human subjects research was not met. Supporting data is available upon request.

There were 4,230 MA plans (19% Low Star Rating, 45% High, and 36% Highest, 5 plans excluded for missing data) and 811 PDP (77% Low, 23% High, and 0% Highest, 3 plans excluded for missing data). Among all plans and medications, coverage barriers were present in 96% of plans. The only barrier was tier ≥3 cost sharing, and no plans required prior authorization or step therapy for any of the medication classes.

In table 1, among MA plans, those with Low Star Rating had the lowest rate of tier ≥3 cost sharing requirements (Low: 91%, High: 96–97%, and Highest: 95–96%). All PDP had tier ≥3 cost sharing for DOAC and ARNI. For SGLT2i, 100% of PDP with Low Star Rating had tier ≥ 3 cost sharing, compared to 82% of High rated plans. Overall, 30-day out-of-pocket costs were greater for the High and Highest Star Rating plans compared to Low Star Rating plans (MA: $45–52 vs $39–40; PDP:$75–86 vs $62–70), except for SGLT2i, among PDP plans, specifically ($52 vs $61).

Table 1:

Summary of coverage barriers and out of pocket costs.

MEDICARE ADVANTAGE PLANS
Plan Star Rating N (%), Mean (SD)	Low N= 819	High N=1995	Highest N=1416	p-value
DOAC coverage barrier	745 (91%)	1929 (97%)	1364 (96%)	<0.001
SGLT2I coverage barrier	745 (91%)	1921 (96%)	1352 (95%)	<0.001
ARNI coverage barrier	745 (91%)	1936 (97%)	1363 (96%)	<0.001
DOAC 30-day out-of-pocket cost	$39 (21)	$45 (28)	$51 (30)	<0.001
SGLT2I 30-day out-of-pocket cost	$39 (21)	$45 (29)	$48 (31)	0.002
ARNI 30-day out-of-pocket cost	$40 (24)	$48 (34)	$52 (36)	0.004
PART D PRESCRIPTION DRUG PLANS
Plan Star Rating N (%), Mean (SD)	Low N=621	High N=190	Highest N=0	p-value
DOAC coverage barrier	621 (100%)	190 (100%)	-	-
SGLT2I coverage barrier	621 (100%)	156 (82%)	-	<0.001
ARNI coverage barrier	621 (100%)	190 (100%)	-	-
DOAC 30-day out-of-pocket cost	$62 (31)	$75 (40)	-	0.009
SGLT2I 30-day out-of-pocket cost	$61 (38)	$52 (30)	-	0.045
ARNI 30-day out-of-pocket cost	$70 (42)	$86 (54)	-	<0.001

Coverage barrier was defined as least one of the following: prior authorization, step therapy, tier ≥3 cost sharing, or no coverage. SD= standard deviation. Mean and SD were round to the nearst $. DOAC= direct oral anticoagulants (apixaban, rivoraxaban), SGLT2i= Sodium-glucose cotransporter-2 inhibitors (empagliflozin, dapagliflozin), ARNI= angiotensin receptor neprilysin inhibitor (sacubitril-valsartan). Low Star Rating (<3.5), High (3.5–4), and Highest (4.5–5)

Our findings demonstrate that for Medicare beneficiaries, higher Medicare Star Rating was not associated with improved medication access or out-of-pocket costs for commonly used, non-generic cardiovascular medications. Specifically, we found that coverage barriers were more common for ARNI, SGLT2i, and DOAC in higher rated MA plans, and for ARNI and DOAC in higher rated PDP plans. Further research is necessary to evaluate the clinical impact of these findings and adjust for potential confounding. Medicare beneficiaries looking to improve access to cardiovascular medications should consider specific details of medication coverage when making enrollment decisions.

We also found that over 96% of Medicare drug coverage plans required tier ≥3 cost sharing requirements for these agents. Such barriers can result in lower adherence, worse clinical outcomes, and disparities in care.¹ Clinicians should be aware that many Medicare beneficiaries will have cost sharing requirements for these medication classes. In prior work, 84% of patients reported the desire to have medication cost conversations with their provider, but only 23% reported having them.⁵

Of note, as a plan-level analysis, we were unable to assess prescription and fill rates or clinical outcomes. Quantity limits and drug subsidies were not included. We included a limited number of medications and did not assess therapeutic alternatives.

We found that the majority of Medicare drug plans had coverage barriers to non-generic, evidenced-based, highly effective cardiovascular medications, entirely through tier ≥3 cost sharing requirements. Additionally, higher Star Rating was not correlated with improved access to medications or lower out-of-pocket cost. Our findings suggest that the current drug plan Star Rating system does not directly guide patients in choosing plans that will improve access to these medications.

Non-standard Abbreviations and Acronyms

ARNI

Angiotensin Receptor Neprilysin Inhibitors

DOAC

Direct Oral Anticoagulants

MA

Medicare Advantage

PDP

Part D Prescription Drug Plans

SGLT2i

Sodium Glucose Cotransporter 2 Inhibitors