Medication adherence and hospital readmissions: A cross-sectional analysis of Medicare Star Ratings performance

The Medicare Star Ratings program, administered by the Centers for Medicare & Medicaid Services, includes a list of quality measures aimed at evaluating the quality of care provided by Medicare health plans. These measures include 3 medication adherence measures (non-insulin antidiabetics, renin-angiotensin system antagonists (RASA), and statins), as well as a plan all-cause readmission (PACR) measure, among dozens of other measures.

To examine the potential association between the 3 Medicare Star Rating medication adherence measures and the PACR measure.

An analysis of the publicly available annual health plan Medicare Star Rating performance data were conducted for the Star Rating years of 2015-2024, except years 2021-2023 when the PACR measure was not assessed by CMS. The primary outcomes were odds ratios (ORs) and 95% confidence intervals (CIs) evaluating the likelihood of a health plan achieving ≥4-stars on the PACR measure if it also earned ≥4-stars or 5-stars on the adherence measure(s).

Health plans that achieved ≥4-stars or 5-stars on the RASA measure had significantly higher odds of achieving ≥4-stars on the PACR measure (OR:1.53, 95% CI:1.30-1.81; OR:1.51, 95% CI:1.26-1.81; respectively), as did plans that achieved ≥4-stars or 5-stars on the statin adherence measure (OR: 1.58, 95% CI:1.31-1.86; OR:1.94, 95% CI: 1.55-2.43; respectively). There was no significant impact for the diabetes adherence measure (≥4-stars OR: 1.10, 95% CI:0.93-1.30; 5-stars OR: 1.09, 95% CI: 0.89-1.33). The likelihood of achieving ≥4-stars on the PACR measure increased non-significantly with the number of adherence measures that achieved 5-stars (all 3 adherence measures OR: 1.53, 95% CI: 1.17-2.00; only 2 adherence measures OR: 1.44, 95% CI: 1.09-1.90; only 1 adherence measure OR: 1.11, 95% CI: 0.87-1.41).

Health plans with higher performance on the Medicare Star Ratings adherence measures had significantly increased odds of high performance on the Medicare Star Ratings PACR measure, suggesting an association between effective medication management and reduced all-cause readmissions.