Physician Perception of Patient Medication Adherence in a Cohort of Medicare Advantage Plans in Texas.

Background: Prescription medication adherence is a known health-related barrier for elderly patients, leading to insufficient disease control and negative health outcomes. The Centers for Medicare & Medicaid Services (CMS) have placed significant emphasis on medication adherence, through the Part D star measures, revolving around treatment for chronic disease states such as hypertension, diabetes, and hyperlipidemia. However, it is unclear if physicians fully grasp the extent of nonadherence within their patient populations with regard to these medications, specifically those patients enrolled in Medicare Advantage Prescription Drug (MA-PD) plans.

Objectives: To (a) determine physicians' perceptions of medication adherence among their patients enrolled in MA-PD plans and (b) compare those perceptions with actual adherence rates obtained from claims data.

Methods: A survey was developed and administered to primary care physicians (PCPs) contracted within a Texas MA-PD plan. The previously validated questionnaire was distributed during an all-PCP quarterly meeting and was collected prior to the meeting's conclusion to increase completion and return rates. PCPs were requested to indicate what percentage of their patients they believed to be adherent to each of the CMS Part D star medication classes, which includes statins, oral antidiabetic drugs (OADs), and reninangiotensin system (RAS) antagonists; what financial category they believe the majority of their patients fall under; and what percentage of their patients receive samples. The PCPs' perceived percentage of adherent patients were compared with the calculated percentage of patients, using a chi-square test at an a priori alpha level of 0.05. The calculated adherence was obtained from pharmacy claims data, meeting the CMS targeted adherence threshold (≥ 80%). This adherence rate was calculated using proportion of days covered (PDC) for all 3 medication categories in each PCP's patient population.

Results: To compare PCP perception of patient adherence and actual adherence, 226 PCPs were used. The sample population shared similar sex and age distribution with the national physician average; however, there was more racial diversity represented. PCP perception of patient adherence, as well as the actual percentage of adherent patients, were significantly (P < 0.05) different across statins, OADs, and RAS antagonists; lowest perceived percentage, as well as actual percentage, were reported for statins. PCP perception of patient adherence and actual percentage of adherent patients were significantly different in the 3 medication categories. PCPs' correct estimations were significantly (P < 0.0001) lower than expected values, while over- and underestimations were significantly (P < 0.0001) higher than the expected values.

Conclusions: PCPs were almost equally likely to over- or underestimate percentage of adherent patients in their patient pools.