Adherence Is Falling for High-Risk Members. Here's What That Means for 2027.
For the first time in roughly a decade, Medicare Part D adherence rates are moving the wrong way. The decline is concentrated in the members who matter most under SDS risk adjustment, and their rates are down about half a percentage point from last year.
In Star Ratings, that isn't small. A half-point swing can move a plan across a cut point, and these measures return to triple weight next year.
What the Data Shows
CMS sends plan sponsors monthly Acumen reports on their adherence measures. The reports run about a month behind, so the latest snapshot covers measurement year 2026 through the end of July. It isn't the full year, but the direction is clear.
The drop is coming from the stratified groups that feed SDS risk adjustment:
- Members under age 55
- Members who qualify for Medicare through disability
- Dual-eligible and low-income subsidy (LIS) members
Across diabetes medications, RAS antagonists and statins, these groups are doing worse than they were a year ago. Historically, adherence rates have climbed year over year. This year they haven't.
Why It's Happening
Two forces seem to be at work.
The first is weighting. In measurement year 2026, the adherence measures carry 1x weight while CMS phases in SDS risk adjustment. Some plans have likely treated this as a year to focus elsewhere. That's an understandable business decision, and it's showing up in the numbers.
The second is market exits. Several national carriers have pulled out of markets where members are sicker and more costly to serve. Those members don't stop needing their medications. Some return to traditional Medicare and manage on their own. Others land at smaller regional plans that may not have the outreach infrastructure to reach them quickly.
Many of those regional plans can't simply leave. Plans that offer Medicaid are often expected to offer Medicare Advantage in the same service areas, so they take on these members whether they planned for them or not.
Why It Matters More in 2027
In measurement year 2027, the SDS risk-adjusted adherence measures go back to triple weight. That puts them among the most heavily weighted measures in the program. If a Star Rating is a GPA, the adherence measures are the five-credit courses.
Cut points don't stand still, either. They've historically risen each year. An 86% rate might have earned three stars a few years ago and only two today. A plan that holds flat is falling behind.
The Risk Adjustment Question Every Plan Is Asking
The question we hear most right now is simple: what will our risk adjustment be?
Plans won't know for certain until CMS releases predicted rates in mid-2027, after the measurement year has closed. The formula itself is public:
Risk Adjusted Adherence Rate = (Unadjusted Rate / Predicted Rate) x Contract Type Unadjusted Rate
The predicted rate is the unknown. It comes down to two levers:
- Member mix. Who your plan serves, and how that changed this year.
- The market. How the same high-risk groups are performing across all plans.
Member mix can shift faster than most plans expect. One regional plan we work with added roughly 30,000 members this year, and its dual-eligible share fell from about 80% to about 40%. That change alone will likely shrink the lift it gets from risk adjustment, even if nothing about its outreach changes.
The reverse happens too. When healthier members leave a plan, the remaining population skews higher risk and the numbers shift underneath it.
With several years of display data, the stratified Acumen rates and a plan's own enrollment changes, our team can build a working estimate of where a plan is likely to land. More important, we can show what rates it needs to reach in 2027 to get there.
What Works With High-Risk Members
High-risk members are harder to reach, and a standard reminder program won't close the gap. The plans making progress get three things right.
- Daily claims data. Pharmacy claims process in real time, every day of the year. A weekly or biweekly feed means calling members who already filled, which wastes outreach and costs trust. Our platform ingests claims daily, so pharmacists reach the right members at the right time.
- Finding members who are hard to find. About a quarter of the phone numbers health plans provide are dead ends. Members change phones often, especially members on low-income programs, and the enrollment file rarely catches up. Because we can see where members fill and who prescribes for them, we can get a current number from their pharmacy or provider.
- Fixing the problem on the call. A prescription transfer, a new prescriber, a refill after a hospital stay. Our team resolves it directly, with the goal of taking 95% of the effort off the health plan and provider. Members who need more get escalated to the plan with the details already in hand.
At the regional plan above, adherence improved about 4 to 5% per measure in the first year, after several flat years with a previous vendor.
Use 2026 to Build for 2027
Falling high-risk adherence is both a warning and an opening. Plans that use the rest of 2026 to understand their member mix and build outreach that reaches high-risk members will start 2027 ahead of the cut points instead of chasing them.
If your plan wants a clearer picture of where its risk-adjusted adherence rates are likely to land, we'd be glad to walk through your numbers. Learn more at here or contact our team today.
