Prescriptions for a >90 day supply, mail-order pharmacy use, and lower copayments and out-of-pocket maximums nearly doubled the chances that older patients adhered to their prescribed heart and diabetes medications, a new study has shown. Findings from the study are published in Medical Care.

The cross-sectional study evaluated electronic medical records and pharmacy data of 129,040 Kaiser Permanente members across three regions who had diabetes and were >65 years old in 2010. The Medicare 5-STAR Quality Rating System metrics were used to study patient adherence for three heart medications commonly prescribed to patients with type 2 diabetes (eg, antihypertensives, statins, antihyperglycemics).

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Researchers found that seniors were about 90% adherent for all three medications when the following system-level factors were in place:

  • Prescribed a 90-day supply
  • Copayments ≤$10
  • Out-of-pocket maximum payments ≤$2,000
  • Used mail-order pharmacy for more than half of the year’s refills

The strongest predictor of achieving STAR-defined medication adherence was a mean prescribed medication days’ supply of >90 days (RR 1.61; P<0.001). Use of mail-order pharmacy to fill medications >50% of the time was separately associated with improved adherence with these medications (RR 1.07 [antihypertensives], 1.06 [antihyperglycemics], 1.07 [statins]; P<0.001). Copayments ≤$10 for 30 days’ supply (RR 1.02 for all; P<0.01) and annual out-of-pocket maximums ≤$2,000 (RR 1.02, 1.01, 1.02, respectively; P<0.01) were also associated with higher adherence for all three medication groups.

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