A Guide for Medicare Advantage Plans: Achieving 4+ Stars on the Toughest Part D Star Measures

For Medicare Advantage plans, high Star Ratings are critically important because they directly impact both financial performance and market competitiveness. Achieving 4 or 5 stars allows Medicare Advantage plans to qualify for quality bonus payments, get higher reimbursements from CMS, attract more beneficiaries during the annual enrollment period, and ultimately grow their market share.

To further underscore the significance of Star Ratings, multiple payers filed lawsuits challenging CMS’ Star Ratings methodology this past October as they saw hundreds of millions of dollars at stake for being a 3.5 star versus a 4 star plan, for example. For 2025, only 40% of plans achieved 4 stars or above, and the percentage of members covered by a 4 star or higher plan has also dropped to 62%—both at the lowest levels in over 5 years.

Many Medicare Advantage plans struggle with certain Part C and Part D measures, but what makes high scores so elusive for some of these measures year after year? We will focus on some of the toughest Part D outcomes measures, which have become increasingly important for Stars Ratings as the weights of Member Experience and Complaints measures has been dialed back in favor of outcomes and clinical process measures for Measure Year (MY) 2025.

The Lowest-Performing Part D Measures and Why They’re Hard to Achieve

For the third year in a row, the average ratings of the triple-weighted adherence measures are among the lowest-performing measures among the Part D measures. With the addition of the Concurrent Use of Opioids and Benzodiazepines (COB) and Polypharmacy Use of Multiple Anticholinergic Medications in Older Adults (Poly-ACH) for MY2025, achieving 4 or more stars may prove to be even more of a challenge. Understanding these measures, why they’re difficult to excel in, and what’s needed for success can set plans on the path to a 4 or 5-star rating.

• Triple-Weighted Adherence Measures: These measures track medication adherence for diabetes, hypertension, and cholesterol management. Members who maintain a Proportion of Days Covered (PDC) of 80% or more are considered adherent and are reported as a percent of those who had two fills of an adherence-eligible medication on unique fill dates in the year.
  
  When tracking these metrics, inclusion criteria, exclusion criteria, and allowable gap days to meet the measure need to be meticulously monitored across a member population. With a low margin for error, as little as 3% can be the difference between a 3-star or 5-star rating, as was the case in 2025 with the RASA adherence measure. This was also the delta between a 2-star and 4-star rating in the 2025 Diabetes Adherence measure. Each of the three adherence measures carries triple the weight in Star Ratings, but the average rating has consistently been between 3 and 3.4 since 2023, indicating they are notoriously difficult to improve.
  
  
• Statin Use in Persons with Diabetes (SUPD): This measure evaluates the percentage of members with diabetes who are prescribed a statin to lower their risk of heart disease. To be eligible for this measure, members aged 40-75 who have filled at least two diabetes medications on unique fill dates need to receive a statin. Not only does this measure require precise targeting for those eligible for the measure, but it also requires a coordinated effort between the plan, prescribers, and the member to achieve the goal. The average rating for this measure for 2025 is an underwhelming 2.8.
  
  
• Medication Therapy Management (MTM) Program Completion Rate for Comprehensive Medication Review (CMR): This measure, scheduled for reintroduction in MY2027, tracks how effectively health plans complete CMRs for eligible members. Health plans have performed relatively well on the CMR Star Measure, with the average rating falling between 3.7 and 3.9 over the past 3 years. However, expanded eligibility criteria in MY2025 present administrative and operational challenges that will likely negatively impact scores.
  
  While the CMR measure is a Display measure for the next two years, the changes are substantial enough that health plans should begin preparing now. The number of eligible members for this measure is expected to increase from 3.6M to 7.1M, and plans need to have a plan in place to scale outreach.
  
  Plans have discretion when targeting members for the CMR measure. To be targeted for a CMR, members must be identified as at-risk beneficiaries via the plan’s drug management program, OR meet the following criteria:
  
  
  1. 1. Members must have multiple chronic diseases. Plans can define this as having at least two or three of these ten core chronic conditions:
        • Alzheimer's disease
        • Bone disease-arthritis (including osteoporosis, osteoarthritis, and rheumatoid arthritis)
        • Chronic congestive heart failure (CHF)
        • Diabetes
        • Dyslipidemia
        • End-stage renal disease (ESRD)
        • Human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS)
        • Hypertension
        • Mental health (including depression, schizophrenia, bipolar disorder, and other chronic/disabling mental health conditions)
        • Respiratory disease (including asthma, chronic obstructive pulmonary disease (COPD), and other chronic lung disorders)
     2. Members targeted must be taking multiple Part D drugs. Plans can define the targeting threshold as patients taking as few as two or as many as eight Part D medications, including Part D maintenance drugs.
     3. Members must spend at least the average annual cost of eight generic drugs, which for 2025 is $1,623.

Members who meet this eligibility criteria must be offered an in-person or telehealth interactive consultation in real-time with a pharmacist or other qualified provider with thorough documentation in a standardized format. Only in the case where the member is cognitively impaired can someone other than the member participate in the CMR on behalf of the member.

While challenging, this is ultimately a positive step. MTM is associated with improvements in medication appropriateness, adherence, dosing, and overall health outcomes, so these changes present an opportunity to deliver more impactful care, which is the intent of the Stars program.

There are also two new Part D measures for MY2025, which will likely present similar challenges to those noted above.

• Concurrent Use of Opioids and Benzodiazepines (COB): This newly introduced measure aims to reduce potentially dangerous interactions and overdoses associated with opioids and benzodiazepines. Members who have ≥30 cumulative days of overlapping use of opioids and benzodiazepines will fall into the measure. Identifying the appropriate individuals who are at risk of qualifying for the measure and proactively intervening can be challenging due to social or behavioral patient histories and the lack of coordinated care.
  
  
• Polypharmacy Use of Multiple Anticholinergic Medications in Older Adults (POLY-ACH): Another new measure, POLY-ACH is used to assess the percentage of individuals aged 65 years and older who are concurrently using two or more unique anticholinergic medications for a period of 30 or more cumulative days of overlap within a measurement year. Impacting this polypharmacy measure requires predictive analytics to trigger interventions before a member falls into the measure.

What Health Plans Need for Success on Challenging Part D Measures

With the exception of the CMR measure, the most difficult Part D measures require continuous, proactive monitoring and interventions to prevent a member from falling in or out of the measure. As health plans navigate the dual challenges of an aging, high-risk population and increasing cost pressures that strain care team resources, prioritizing care efficiently is more critical than ever.

Plans that achieve 4 or more stars on these challenging measures leverage a data-driven approach supported by a robust infrastructure. This ensures resources are focused on the members who need it most while driving better outcomes and maintaining operational efficiency. Here’s what health plans need to have in place:

1. Ongoing Monitoring and Data Analytics: Continuous monitoring of pharmacy claims, medical claims, member files, and other datasets is essential. Layering AI-driven predictive analytics in real-time can help identify members at risk of non-adherence or inappropriate medication use.
   
   
2. Proactive Interventions: For measures like medication adherence and polypharmacy, appropriate and timely interventions that prevent the member from falling in or out of the measure are key. This could include outreach to members, coordinating with providers, and delivering tailored support that addresses individual barriers to medication use.
   
   
3. Efficient Use of Care Team Resources: Health plans need to optimize their care teams to focus on high-risk, high-impact interventions. This involves using data to prioritize cases and assign resources effectively to manage complex, high-need populations.
   
   
4. Provider Engagement: Building trust and fostering engagement with providers is essential for improving Star Ratings on that rely on coordinated care. To ensure that providers take meaningful action, recommended interventions need to include patient-specific context and be supported by clear clinical guidelines, demonstrating how these actions can directly improve a patient’s outcomes.
   
   
5. Technology and AI-Driven Platforms: Advanced platforms that leverage AI and machine learning can enhance a health plan’s ability to meet these goals. These platforms can dynamically predict high-risk patients using the latest data, recommend the most impactful interventions, and streamline the workflow for care teams.

Why Health Plans Need to Act Early

The clock is ticking. Achieving a high Star Rating on the most challenging Part D measures requires a strategy to be implemented as early as possible in the calendar year. Proactive planning allows for more effective monitoring, early intervention, and course-correcting if challenges arise throughout the year. A head start in planning also gives health plans time to engage with more members, especially with CMRs, which can surface any gaps before they become critical.

Why Partner with Arine?

At Arine, we’ve helped health plans boost their Star Ratings in less than one year. Our AI-powered platform supports health plans in continuous monitoring, proactive interventions, and efficient use of care resources, with a specific focus on challenging Part D adherence and utilization measures. From predictive analytics to real-world data-driven insights, our platform is designed to address the unique barriers that prevent members from achieving optimal medication use and health outcomes.

It's not too late. Schedule a demo today to learn how we can help you succeed on even the most challenging Part C and Part D and set your health plan on the path to 4+ Star ratings.