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Medication adherence: a moving target?
  1. Robin Mathews
  1. Division of Cardiology, Duke University Medical Center, Durham, North Carolina, USA
  1. Correspondence to Dr Robin Mathews, Division of Cardiology, Duke Clinical Research Institute, Duke University Medical Center, Durham, NC 27708-0187, USA; robin.mathews{at}

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The landscape of healthcare delivery is constantly evolving in an ongoing attempt to provide effective and high-quality care. The Institute of Medicine defines quality as, ‘The degree to which health services for individuals and populations increase the likelihood of desired health outcomes and are consistent with current professional knowledge.'1 Process metrics are routinely used to assess adherence to guideline-based recommendations in patients admitted with acute coronary syndrome (ACS).2 Though we see near-ubiquitous use of evidence-based treatments among hospitalised patients, outpatient adherence to these prescribed therapies is poor. As medication non-adherence has been associated with worse outcomes and higher costs,3 it has become an area of particular interest to policy-makers. The article by Gonzalez et al, published in Heart,4 attempts to examine this timely and important topic.

The authors use a governmental policy change as a natural experiment to assess in pre–post fashion the impact of medication cost sharing on patient adherence to common secondary prevention cardiac therapies after hospital discharge for ACS. In this observational analysis of 10 563 patients discharged from 2009 to 2011 in the Valencia Health System, the authors measured prescription fill rates to assess adherence before and after a 2012 policy change by the regional government where pensioners were expected to cover 10% of medication cost (compared with none historically), and middle-to-high-income individuals saw an increase in out-of-pocket medication cost from 40% to either 50% or 60%. The authors found that adherence worsened when cost burden was shifted to patients. The largest effects were noted for higher cost medications—ACE inhibitors or angiotensin receptor blockers (ACEIs/ARBs) and statins—among pensioners with a 6.8% and 8.3% reduction in adherence, respectively. Among the higher income group, decreased adherence was noted only among statins (7.8%). On follow-up, however, adherence returned to baseline at about 12 months for higher income patients and within 21 months for pensioners.

This study confirms prior research that has found poor medication adherence among cardiac patients even soon after a myocardial infarction with little improvement in prescription filling patterns even many months later.Though not included in the analysis, premature discontinuation of dual antiplatelet therapy has been associated with serious adverse events such as stent thrombosis in patients treated with percutaneous coronary intervention. The authors found a modest decrease in adherence that was attenuated over the follow-up period and eventually returned to baseline. This downstream improvement in adherence is an interesting finding. Possible explanations may include, as the authors suggest, the relatively small shifts in cost burden associated with the policy shift that led to only a temporary effect on patients. Evaluation of interventions to improve adherence by reducing the financial burden of medications have noted mixed results. In the randomised Post-Myocardial Infarction Free Rx Event and Economic Evaluation (MI FREEE) trial, Choudry et al found that reducing patient copayments was associated with improved medication use.5 Strategies such as this—referred to as value-based insurance design—aim to improve long-term adherence. However, improvements in adherence in MI FREEE were modest with copayment reduction alone, suggesting that additional measures are needed to improve medication-taking behaviour and outcomes. Other factors may be more strongly associated with medication adherence than out-of-pocket cost alone such as health literacy and sociodemographic characteristics.

Outcomes are not assessed in this analysis so it is unknown if the decline in adherence was related to any increase in adverse events. The intervention cohort consisting of pensioners were older and most likely had more comorbidities and, subsequently, higher overall cardiovascular risk. Medication non-adherence in a high-risk pool is even more critical to reduce disease complications. Other considerations such as fixed incomes make this group especially sensitive to increased out-of-pocket costs compared with their higher income counterparts. The differential effects of the policy intervention between the two groups noted in this study highlight the complexity of the patient adherence discussion in broad terms; patients are unique and respond differently to similar interventions. Health system factors, patients’ comorbidities (including mental health issues) and therapy-related factors (such as side effects) are just some of the key factors that contribute to understanding patient adherence.6

The use of metrics, such as aspirin use in ACS and door-to-balloon time for ST elevation myocardial infarction, provide an objective assessment for the quality of care delivered, and also function as a goal for hospitals to strive for when evaluating their own performance.2 As hospitals continue to improve and achieve very high rates of adherence to performance metrics, new relevant metrics need to be identified to ensure ongoing progress in the quality improvement (QI) movement. Despite its complexity, the challenge of improving medication adherence across all healthcare systems can become the new QI frontier. Higher adherence has been associated with better outcomes, and one can argue that health systems that promote better adherence through their policies, provide higher quality of care. Traditionally, the burden has exclusively been placed on patients to ensure proper adherence to medications prescribed to them; however, there is increasing recognition that hospitals and health systems can impact downstream patient adherence even after a patient is discharged.

The transition of care from the hospital setting to home is a critical period for the patient. Though hospitals have implemented processes to address issues such as outpatient provider communication, patient education and physician follow-up, the processes for these transitions of care are fragmented and vary across health systems. Though the uniformity achieved through performance metrics may be particularly beneficial, further investigation is needed to better identify hospital level factors that strongly contribute to downstream medication adherence. Solutions that attempt to bridge the critical gap between inpatient discharge and outpatient follow-up that engage a patient’s interest in his or her own health may represent the best opportunity for success. Interventions that foster upfront education followed by ongoing communications between the patients and the healthcare system through early physician follow-up as well as outpatient tele-monitoring and pharmacist interactions are just some options that should be considered.6

Commercial and governmental prescription claims databases have been used to assess patient-level adherence through prescription refill but also can be harnessed to assess medication adherence across hospital systems.7 Furthermore, as administrative and clinical data collection become more comprehensive, hospital adherence rates can be adjusted for patient and hospital characteristics to allow for a more fair and accurate comparison between multiple centres that vary by geography, payer mix and patient population. Initiatives such as levying penalties on hospitals for ‘preventable’ readmissions are now increasingly common.8 Though such programmes are not without limitations, the intent behind them is to mitigate hospital factors that can influence adverse outcomes. Likewise, the use of hospital-level adherence metrics encourages hospital to enact reasonable and impactful policies that increase an individuals ability to be adherent.

Medication non-adherence is a widespread and pervasive problem across all disease states and one that spans the breadth of health delivery systems across the globe. It is time for the medication adherence paradigm to shift and be redefined in a place where patients and their providers share a mutual interest in achieving better adherence. Though patients may bear the final responsibility, it is incumbent on us as providers to create systems that place patients in the best position to advocate for their own health. Ultimately, solutions to meet this complex challenge need to be creative, pragmatic and scalable.



  • Competing interests None declared.

  • Provenance and peer review Commissioned; internally peer reviewed.

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