Study Shows Patient Self Reports Overestimated And Pharmacy Fills Underestimated Medication Persistence Agreement and Accuracy of Medication Persistence Identified by Patient Self-report vs Pharmacy Fill A Secondary Analysis of the Cluster Randomized ARTEMIS Trial

Amandeep Singh, M.D.
By Amandeep Singh, M.D. on

In an original investigation done by Dr. Alexander C. Fanaroff et al and recently published in JAMA Cardiology, it was found that there was discordance in medication persistence as measured by patient-reported and the pharmacy fill data. The patient self-reports overestimated and pharmacy fill data underestimated medication persistence. Those who had non-persistence by both measures had the highest rate of major adverse cardiovascular events (MACE). The authors also noted the need for giving preference to interventions that will promote medication-taking behavior.

The authors wanted to do this post hoc analysis of ARTEMIS (Affordability and Real-world Antiplatelet Treatment Effectiveness After Myocardial Infarction Study) trial to find the accuracy and determination of the degree of methods used to find non-persistence rates of P2Y12 inhibitors while assessing by patient-reported and pharmacy fills. This analysis used data from the ARTEMIS trial that had enrolled 287 hospitals(131 for intervention and 156 for usual care). The nonpersistence was defined as a gap of 30 days or more in the supply or use. Patients were classified as cumulative medication persistence. Around 10 102 patients were followed up for 1 year. 8373 patients(82.9%) had pharmacy fills . Intervention arm of 3705 patients received copayment vouchers for P2Y12 inhibitors and around 944 patients had randomly undergone phlebotomy to determine drug levels in the blood at 3, 6, 9 and 12 months(denoted by κ).

Historically, persistence was measured by asking patients, essentially, self-report. Health systems have increasingly made pharmacy fill data accessible to physicians to help them identify persistence “objectively.” Our study shows that using either of these methods in isolation to target non-persistent patients for interventions that increase persistence is unlikely to be the best method, and that best practices should incorporate both of these methods.”- Dr. Alexander C. Fanaroff M.D., M.H.S.

Dr. Alexander C. Fanaroff who is currently working as Assistant Professor of Medicine, Division of Cardiology at the University of Pennsylvania School of Medicine when asked about the study findings in relation to evidence in the field states, “There are a few key findings from our study. First, we re-demonstrate, in the context of a pragmatic clinical trial, that persistence is higher by self-report than pharmacy fill: 15% of patients self-reported non-persistence, but 48% of patients were non-persistent by pharmacy fill data. Second, when we looked at the agreement between the methods, the two methods quite frequently did not agree:  50% of patients were persistent by both methods, 13.5% were non-persistent by both methods, 34.8% reported that they were persistent but were non-persistent by pharmacy fill, and 1.8% reported that they were non-persistent but were actually persistent by pharmacy fill records. Third, due to the nature of the ARTEMIS trial, we had two other methods of measuring persistence that we could leverage to figure out whether the patient report or pharmacy fill data was more often “correct”: copayment assistance vouchers and P2Y12 inhibitor serum drug levels. We had serum drug levels for a random sample of patients in ARTEMIS, and we found limited agreement beyond chance between serum drug levels and persistence as measured by pharmacy fill and patient report, which did not help sort out which method was more “correct.” In the intervention arm, patients used vouchers to have copayments for P2Y12 inhibitors waived, and we were able to track when vouchers were used. Using the voucher data, 20% of patients that self-reported persistence but were characterized by pharmacy fill data as non-persistent actually were persistent, suggesting that pharmacy fill data underestimates persistence by roughly that amount. Lastly, we looked at clinical outcomes by persistence category, and found that patients persistent by both methods had the best outcomes, patients non-persistent by both methods had the worst outcomes, and patients with discordant persistence had outcomes intermediate between concordantly persistent and non-persistent patients.”

The investigators noted that the study had some limitations being chiefly the Hawthorne effect, due to the trial studying medication persistence, and generalizability to people without insurance, the patients who are treated in routine clinical practice may have a higher persistence as compared to the study population who self-reported only during the follow up of one year. Recurrent MI or stroke could affect the persistence. Phlebotomy timing with respect to the last P2Y12 inhibitor intake was not noted.

To view the slides related to this investigation, Courtesy: Dr. Alexander C. Fanaroff M.D., M.H.S. , please click here

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