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 six common medications to medications brought to a study visit in 2011–2013 for the Atherosclerosis Risk in Communities Study (ARIC). The combined data consisted of 3,027 medication events (claims, medications possessed or both) for 2,099 ARIC participants. Multinomial logistic regression estimated the association of concordance (Visit Only, Part D Only, or Both) with self-reported medication adherence while controlling for socio-demographic characteristics, veteran status, and availability under Generic Drug Discount Programs (GDDPs). Results Relative to participants with high adherence (p<0.05), medication events for participants with low adherence were approximately 25 percentage points less likely to match and more likely to be Visit Only. The results were similar but smaller in magnitude (approximately 2–3 percentage points) for participants with medium adherence. Compared to 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 GDDP 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.

Predictors of Medication Adherence in the Elderly: The Role of Mental Health

“…Medication adherence was self-reported and not specific to individual disease states; the latter factor is a strength, though studies validating concordance of the MGLS have only assessed adherence in individual disease states (Shi et al, 2010). Errors in selfreport of adherence, both deliberate and unintentional, could bias the estimated associations, though a comparison of self-reported adherence using the MGLS supported the validity of the scale (Savitz et al, 2017). Random error in reported adherence would bias estimates toward zero, but we still find statistically significant associations for many factors including mild cognitive impairment versus normal cognition.…”

Adherence to colorectal cancer screening measured as the proportion of time covered

“…19 Alternative approaches, such as “proportion of time covered,” 20–22 may be better suited to accommodate these challenges and measure adherence across the entire screening process. Although proportion of time covered is frequently used in medication adherence research as a valid surrogate of adherence, 23 and emerging evidence support its use for measuring hepatocellular carcinoma surveillance 24 , there are no data to show if and how this approach may be used to measure CRC screening adherence. Compared with traditional adherence measures, time covered approaches provide a better measure of adherence by: (1) accounting for quality, timing, and results of screening examinations; (2) not penalizing patients for examinations performed just outside the recommended interval; and (3) including all available follow-up time.…”

Antihypertensive adherence and outcomes among community‐dwelling Medicare beneficiaries: the Atherosclerosis Risk in Communities Study

“…We chose to use Part D reports of medication use instead of self-reports because other analyses have shown a high rate of concordance between Part D claims and selfreports, except for certain groups such as veterans, 9 and that the self-reports may overstate adherence. 10 However, the rates of more than 80% PDC calculated under this analysis are substantially lower than the self-report at the baseline AFU that 93% of analysis sample members who reported being told by their physician that they had high Unadjusted cumulative incidence of outcomes, stratified by receipt of antihypertensive therapy during ongoing periods blood pressure also reported taking antihypertensives. If the true antihypertensive drug adherence rates are relatively high for the ARIC cohort, then it may be difficult to obtain a good estimate of the effects of antihypertensive drug treatment on outcomes.…”

“…Part D claims are extremely useful for estimating PDC for prescriptions filled under Part D, but the data files are potentially missing prescriptions that may have been filled through other sources (e.g., Veteran Administration pharmacies). We chose to use Part D reports of medication use instead of self‐reports because other analyses have shown a high rate of concordance between Part D claims and self‐reports, except for certain groups such as veterans, and that the self‐reports may overstate adherence . However, the rates of more than 80% PDC calculated under this analysis are substantially lower than the self‐report at the baseline AFU that 93% of analysis sample members who reported being told by their physician that they had high blood pressure also reported taking antihypertensives.…”

“…While not a direct measure of medication prescription or adherence, claim-based measures have been shown to be highly concordant with more direct measurement of medication use (e.g., pill counts as well as self-reported use) 8,9 and to be associated with self-reported adherence. 10 Using National Drug Codes provided on Part D claims, we assigned antihypertension agents to classes; products containing multiple agents were assigned to multiple classes as appropriate. For this analysis, proportion days covered (PDC) was used to assess adherence to antihypertensive medication classes.…”