Adherence to antiepileptic drugs among diverse older Americans on Part D Medicare

Epilepsy Behav. 2017 Jan:66:68-73. doi: 10.1016/j.yebeh.2016.10.017. Epub 2016 Dec 27.

Abstract

Introduction: Older minority groups are more likely to have poor AED adherence. We describe adherence to antiepileptic drugs (AEDs) among older Americans with epilepsy.

Methods: In retrospective analyses of 2008-2010 Medicare claims for a 5% random sample of beneficiaries augmented by minority representation, epilepsy cases in 2009 were those with ≥1 claim with ICD-9345.x or ≥2 with 780.3x, and ≥1 AED. New-onset cases had no such claims or AEDs in the year before the 2009 index event. We calculated the Proportion of Days Covered (PDC) (days with ≥1 AED over total follow-up days) and used logistic regression to estimate associations of non-adherence (PDC <0.8) with minority group adjusting for covariates.

Results: Of 36,912 epilepsy cases (19.2% White, 62.5% African American (AA), 11.3% Hispanic, 5.0% Asian and 2% American Indian/Alaskan Native), 31.8% were non-adherent (range: 24.1% Whites to 34.3% AAs). Of 3706 new-onset cases, 37% were non-adherent (range: 28.7% Whites to 40.5% AAs). In adjusted analyses, associations with minority group were significant among prevalent cases, and for AA and Asians vs. Whites among new cases. Among other findings, beneficiaries from high-poverty ZIP codes were more likely to be non-adherent than their counterparts, and those in cost-sharing drug benefit phases were less likely to be non-adherent than those in deductible phases.

Conclusion: About a third of older adults with epilepsy have poor AED adherence; minorities are more likely than Whites. Investigations of reasons for non-adherence, and interventions to promote adherence, are needed with particular attention to the effect of cost-sharing and poverty.

Keywords: Adherence; Epilepsy; Medicare; Older adults; Part D coverage.

MeSH terms

  • Age Factors
  • Aged
  • Aged, 80 and over
  • Anticonvulsants / economics
  • Anticonvulsants / therapeutic use*
  • Cohort Studies
  • Cost-Benefit Analysis / methods
  • Epilepsy / drug therapy*
  • Epilepsy / ethnology*
  • Epilepsy / psychology
  • Ethnicity* / psychology
  • Female
  • Humans
  • Male
  • Medicare Part D / economics
  • Medicare Part D / trends*
  • Medication Adherence / ethnology*
  • Medication Adherence / psychology
  • Retrospective Studies
  • United States / ethnology

Substances

  • Anticonvulsants