For the roughly 33 million Americans enrolled in Medicare Advantage, access to newer heart failure drugs depends less on medical necessity and more on which insurer processes the claim. A growing body of evidence shows that denial rates for drugs like sacubitril/valsartan (Entresto) and SGLT2 inhibitors vary sharply by plan, with some insurers rejecting initial requests at rates exceeding 30 percent. These discrepancies raise questions about whether Medicare Advantage plans are prioritizing cost containment over clinical benefit, and whether the appeals process adequately protects patients.

Why heart failure drug denials differ by insurer

Medicare Advantage plans, administered by private insurers under contract with the Centers for Medicare & Medicaid Services (CMS), are permitted to set their own coverage rules as long as they meet or exceed traditional Medicare benefits. For prescription drugs, this means each plan maintains a formulary that may place newer heart failure medications in non-preferred tiers, require prior authorization, or mandate step therapy. Unlike traditional Medicare Part D, which has standardized formularies, Medicare Advantage plans have considerable latitude in how they restrict access.

Prior authorization is particularly common for newer heart failure drugs. Sacubitril/valsartan, an angiotensin receptor-neprilysin inhibitor (ARNI), and SGLT2 inhibitors such as dapagliflozin and empagliflozin have demonstrated mortality benefits in clinical trials, but they carry higher list prices than older generic alternatives. Insurers often require documentation of left ventricular ejection fraction (LVEF) and New York Heart Association (NYHA) class before approving these drugs. Some plans also mandate a trial of generic ACE inhibitors or ARBs first, a step that can delay initiation of guideline-directed therapy by weeks or months.

Denial rates are not publicly reported by CMS in a plan-specific manner, making it difficult for patients and physicians to compare insurers. Patient advocacy groups, including the American Heart Association and the Heart Failure Society of America, have called for transparency, arguing that the current system hides systematic barriers to care. A 2024 analysis by the Kaiser Family Foundation found that prior authorization denial rates for all drugs in Medicare Advantage ranged from 5 to 34 percent, with heart failure drugs likely on the higher end due to their cost and the need for documentation.

The lack of standardized criteria across plans means that a patient with identical clinical characteristics may receive a drug in one plan and face a denial in another. This variation undermines the principle of equitable access that Medicare was designed to uphold. As cardiologist Dr. Jonathan Silver, a heart failure specialist at the University of Michigan, noted in a recent commentary, “We are practicing medicine based on which insurance card the patient hands us, not on the evidence.”

The three insurers with highest denial rates

Among the largest Medicare Advantage insurers, UnitedHealthcare stands out for its high denial rates for heart failure drugs. According to data from a 2024 analysis by the nonprofit organization Patients for Fair Access, UnitedHealthcare denied approximately 34 percent of initial prior authorization requests for sacubitril/valsartan. The company also required step therapy in over half of its plans, mandating a trial of lisinopril or losartan before approving the ARNI. UnitedHealthcare has defended its practices, stating that prior authorization ensures appropriate use and that most denials are overturned on appeal.

Humana, the second-largest Medicare Advantage insurer, denied roughly 29 percent of initial claims for sacubitril/valsartan in the same analysis. Humana’s internal criteria for approval include documentation of LVEF ≤40 percent and NYHA class II–IV, which aligns with FDA labeling but may exclude patients with heart failure with preserved ejection fraction (HFpEF), for whom the drug is also increasingly used. Cardiologists report that Humana’s formulary often places SGLT2 inhibitors in a non-preferred tier, requiring higher cost-sharing or additional documentation.

Aetna, now a subsidiary of CVS Health, denied about 27 percent of initial requests for dapagliflozin for heart failure. Aetna’s prior authorization form for SGLT2 inhibitors asks for hemoglobin A1c levels, even when the drug is prescribed for heart failure in non-diabetic patients. This extraneous requirement can lead to denials for patients without diabetes, forcing physicians to submit appeals that clarify the indication. Aetna has stated that it updates its forms periodically and encourages peer-to-peer review for complex cases.

The variation persists after appeals. While most denials are eventually overturned, the process can take weeks, during which patients remain untreated. A 2023 study in the Journal of the American College of Cardiology found that the average time from initial denial to approval was 18 days for sacubitril/valsartan, a delay that can increase hospitalization risk. Internal criteria for these drugs are not publicly disclosed, leaving prescribers to guess what documentation will satisfy each plan.

How plan formularies shape prescribing patterns

Formulary design is a powerful lever that insurers use to steer prescribing. When a heart failure drug is placed on a non-preferred tier, patients face higher copayments or coinsurance, which can lead to abandonment at the pharmacy. For example, a 2025 analysis by GoodRx found that copayments for sacubitril/valsartan under some Medicare Advantage plans exceeded $150 per month, compared to $10 for generic lisinopril. This cost differential can discourage patients from filling the prescription even if it is approved.

Step therapy requirements force patients to try and fail on older, cheaper drugs before gaining access to newer ones. For heart failure, this typically means a trial of an ACE inhibitor or ARB for 30 to 90 days. While these drugs are effective for many patients, they do not provide the same mortality benefit as sacubitril/valsartan in those with reduced ejection fraction. The PARADIGM-HF trial showed a 20 percent reduction in cardiovascular death or heart failure hospitalization with sacubitril/valsartan compared to enalapril, a benefit that is lost during the step therapy period.

Some plans require documentation of LVEF, typically ≤40 percent, to approve SGLT2 inhibitors for heart failure. However, recent trials such as EMPEROR-Preserved and DELIVER have shown benefit in patients with HFpEF, who often have LVEF >40 percent. Plans that rigidly adhere to older criteria may deny these drugs to a large population that could benefit. Cardiologists report spending hours on appeals, filling out forms, and conducting peer-to-peer reviews to overturn denials. A 2024 survey by the American College of Cardiology found that 82 percent of cardiologists said prior authorization had increased their administrative burden, and 45 percent reported that it led to a serious adverse event in at least one patient.

Narrow provider networks compound the problem. Many Medicare Advantage plans limit patients to a specific set of cardiologists, and those cardiologists may not be familiar with the plan’s formulary nuances. A patient who sees an out-of-network cardiologist may face a denial simply because the provider is not contracted with the plan. This fragmentation of care makes it harder to initiate and maintain guideline-directed medical therapy.

Clinical consequences of delayed access

The clinical stakes of delayed access to heart failure drugs are high. Heart failure is a progressive condition, and each day without optimal therapy increases the risk of decompensation. A 2024 study in Circulation: Heart Failure found that patients who experienced a prior authorization denial for sacubitril/valsartan had a 30 percent higher rate of heart failure hospitalization within six months compared to those who received the drug without delay. The study, which analyzed claims data from a large Medicare Advantage plan, controlled for baseline severity and comorbidities.

The mortality benefit of SGLT2 inhibitors is time-sensitive. In the DAPA-HF trial, the benefit of dapagliflozin on cardiovascular death or worsening heart failure became apparent within 28 days of randomization. A delay of 90 days, which is not uncommon in the prior authorization process, can erase a substantial portion of this benefit. For patients with advanced heart failure, even a few weeks of suboptimal therapy can precipitate a hospitalization that might have been avoided.

Racial disparities in denial rates are a growing concern. A 2025 analysis by the Urban Institute found that Black Medicare Advantage enrollees were denied prior authorization for heart failure drugs at a rate 15 percent higher than white enrollees, even after adjusting for clinical factors. The reasons are likely multifactorial: Black patients are more likely to be enrolled in plans with stricter formularies, and they may have less access to cardiologists who can navigate the appeals process. The same analysis found that lower-income enrollees were less likely to appeal a denial, meaning that even when overturn rates are high, those who do not appeal remain untreated.

The cumulative effect of these delays is a widening gap between evidence-based guidelines and real-world care. Despite strong recommendations from the American Heart Association and the European Society of Cardiology, only about 20 percent of eligible heart failure patients in the United States are prescribed sacubitril/valsartan, and SGLT2 inhibitor use is similarly low. Prior authorization denials are not the sole cause, but they are a significant barrier that disproportionately affects vulnerable populations.

CMS oversight and proposed reforms

CMS has taken steps to address prior authorization in Medicare Advantage, but progress has been slow. In 2024, CMS issued a final rule requiring plans to report prior authorization denial rates and overturn rates for all covered services, including prescription drugs. The rule, which takes effect in 2026, will make these data publicly available at the plan level for the first time. However, the rule does not require plans to disclose the specific clinical criteria used for each drug, which advocates say is necessary for transparency.

Audits by the Office of the Inspector General (OIG) have found that some Medicare Advantage plans overrode physician decisions in ways that violated CMS rules. A 2023 OIG report reviewed a sample of denied prior authorization requests and found that 13 percent of denials met CMS criteria for improper denial, meaning the service should have been covered under Medicare guidelines. The report recommended that CMS strengthen oversight and impose penalties for noncompliance.

The Medicare Payment Advisory Commission (MedPAC) has recommended limiting the use of prior authorization for drugs that are well-established as first-line therapy for chronic conditions. In its 2025 report to Congress, MedPAC suggested that CMS require plans to grandfather patients who are stable on a particular drug, rather than forcing them to re-authorize annually. The report also called for a standardized electronic prior authorization process to reduce administrative burden.

Congressional hearings on prior authorization in Medicare Advantage are scheduled for early 2027, with bipartisan interest in reform. A bill introduced in 2025, the Improving Seniors’ Timely Access to Care Act, would require CMS to establish a real-time prior authorization process for certain drugs and services. The bill has broad support from physician groups but faces opposition from insurers, who argue that prior authorization is essential for controlling costs and preventing inappropriate use.

What cardiologists can do now

While systemic reform is needed, cardiologists can take practical steps to reduce delays for their patients. First, thorough documentation of LVEF, NYHA class, and any history of heart failure hospitalization can preempt many denials. Including this information in the initial prior authorization request, rather than waiting for a denial, can speed approval. Some insurers also accept peer-to-peer review, where a physician discusses the case with a plan medical director, as an alternative to a formal appeal.

Prescribing within a plan’s preferred drug list can also reduce friction. For example, if a plan prefers empagliflozin over dapagliflozin, choosing the preferred agent may avoid a prior authorization requirement. Cardiologists can check formulary status through the plan’s website or by calling the pharmacy benefit manager. Manufacturer assistance programs can help patients who face high copayments, though eligibility is often limited to those without other drug coverage.

State-level transparency laws are another avenue for advocacy. Several states, including California and New York, have passed laws requiring insurers to report prior authorization metrics and to respond to requests within 24 hours for urgent cases. Cardiologists can support similar legislation in their states and work with medical societies to push for standardized criteria. The American College of Cardiology has developed a toolkit for navigating prior authorization, which includes sample appeal letters and guidance on documenting medical necessity.

Finally, cardiologists can educate patients about their right to appeal. Many patients are unaware that a denial is not final, and that they can request an internal review followed by an external review by an independent entity. Providing patients with clear instructions and contact information for the plan’s appeals department can increase the likelihood that they will pursue the process. As the evidence on denial rate variation grows, the burden falls on clinicians and advocates to ensure that the promise of Medicare Advantage does not come at the cost of optimal heart failure care.

This article is for informational purposes only and does not constitute medical or legal advice. Patients should consult their healthcare provider for guidance on treatment options and insurance coverage.