title: A Comparison of Self-reported Medication Adherence to Concordance Between Part D Claims and Medication Possession.
abstract: OBJECTIVE
  Medicare Part D claims indicate medication purchased, but people who are not fully adherent may extend prescription use beyond the interval prescribed. This study assessed concordance between Part D claims and medication possession at a study visit in relation to self-reported medication adherence.
  
  
  METHODS
  We matched Part D claims for 6 common medications to medications brought to a study visit in 2011-2013 for the Atherosclerosis Risk in Communities study. The combined data consisted of 3027 medication events (claims, medications possessed, or both) for 2099 Atherosclerosis Risk in Communities study participants. Multinomial logistic regression estimated the association of concordance (visit only, Part D only, or both) with self-reported medication adherence while controlling for sociodemographic characteristics, veteran status, and availability under Generic Drug Discount Programs.
  
  
  RESULTS
  Relative to participants with high adherence, medication events for participants with low adherence were approximately 25 percentage points less likely to match and more likely to be visit only (P<0.001). The results were similar but smaller in magnitude (approximately 2-3 percentage points) for participants with medium adherence. Compared with females, medication events for male veterans were approximately 11 percentage points less likely to match and more likely to be visit only. Events for medications available through Generic Drug Discount Programs were 3 percentage points more likely to be visit only.
  
  
  CONCLUSIONS
  Part D claims were substantially less likely to be concordant with medications possessed at study visit for participants with low self-reported adherence. This result supports the construction of adherence proxies such as proportion days covered using Part D claims.
authors.affiliation: *Department of Health Policy & Management †Cecil G. Sheps Center for Health Services Research, The University of North Carolina at Chapel Hill ‡UNC Eshelman School of Pharmacy, Chapel Hill, NC §College of Pharmacy, King Saud University, Riyadh, Kingdom of Saudi Arabia.
authors.forename: Samuel T
authors.initials: ST
authors.lastname: Savitz
authors.forename: Sally C
authors.initials: SC
authors.lastname: Stearns
authors.forename: Lei
authors.initials: L
authors.lastname: Zhou
authors.forename: Emily
authors.initials: E
authors.lastname: Thudium
authors.forename: Khalid A
authors.initials: KA
authors.lastname: Alburikan
authors.forename: Richard
authors.initials: R
authors.lastname: Tran
authors.forename: Jo E
authors.initials: JE
authors.lastname: Rodgers
mesh_terms: D000367:Age Factors; D050197:Atherosclerosis / Q000188:drug therapy; D004363:Drug Utilization; D005260:Female; D006801:Humans; D007344:Insurance Claim Reporting / Q000706:statistics & numerical data*; D007345:Insurance Claim Review / Q000706:statistics & numerical data*; D008297:Male; D054524:Medicare Part D / Q000706:statistics & numerical data*; D057566:Self Report; D014481:United States; D016903:Drug Monitoring