A systematic literature review comparing methods for the measurement of patient persistence and adherence

<p><b>Objectives:</b> A systematic literature review was conducted comparing different approaches estimating persistence and adherence in chronic diseases with polypharmacy of oral and subcutaneous treatments.</p> <p><b>Methods:</b> This work followed published guidance on performing systematic reviews. Twelve electronic databases and grey literature sources were used to identify studies and guidelines for persistence and adherence of oral and subcutaneous therapies in hypercholesterolemia, type 2 diabetes, hypertension, osteoporosis and rheumatoid arthritis. Outcomes of interest of each persistence and adherence data collection and calculation method included pros: accurate, easy to use, inexpensive; and cons: inaccurate, difficult to use, expensive.</p> <p><b>Results:</b> A total of 4158 records were retrieved up to March 2017. We included 16 observational studies, 5 systematic reviews and 7 guidelines, in patients with hypercholesterolemia (<i>n</i> = 8), type 2 diabetes (<i>n</i> = 4), hypertension (<i>n</i> = 2), rheumatoid arthritis (<i>n</i> = 1) and mixed patient populations (<i>n</i> = 13). Pharmacy and medical records offer an accurate, easy and inexpensive data collection method. Pill count, medication event monitoring systems (MEMs), self-report questionnaires and observer report are easy to use. MEMS and biochemical monitoring tests can be expensive. Proportion of days covered (PDC) was recommended as a gold standard calculation method for long-term treatments. PDC avoids use of days’ supply in calculation, hence is more accurate compared to medication possession ratio (MPR) to assess adherence to treatments in chronic diseases.</p> <p><b>Conclusions:</b> Decisions on what method to use should be based on considerations of the route of medication administration, the resources available, setting and aim of the assessment. Combining different methods may provide wider insights into adherence and persistence, including patient behavior.</p

A systematic review to assess adherence and persistence with statins

<p><b>Objective:</b> To identify and assess studies published over a 10 year period up to February 2016 which measure adherence or persistence with statins, to summarize their methods, strengths and weaknesses and to summarize evidence linking statin adherence/persistence with risk of cardiovascular events.</p> <p><b>Methods:</b> Electronic databases and abstracts from four major cardiovascular disease conferences were searched from January 2005 to February 2016. The study selection process was performed by two reviewers working independently. Studies were included if they reported data regarding patient adherence or persistence with statins in adults with primary hypercholesterolemia, using any type of study design or length of follow-up. One reviewer extracted the study data and assessed study quality, which was checked by a second reviewer independently. Given the heterogeneity between the included studies a narrative critique and summary is presented.</p> <p><b>Results:</b> We report on 84 real world studies which aimed to assess adherence or persistence with statins. The majority of studies concluded that good adherence/persistence was associated with reduction in cardiovascular events and mortality. In two studies high intensity statin regimens were associated with poorer patient adherence when compared to low intensity statins. Adherence and persistence with statin therapy also has an impact on hospitalization costs and other cardiovascular disease (CVD) related costs.</p> <p><b>Conclusions:</b> Adherence and persistence are associated with a reduction in CVD events and mortality. There was limited evidence to suggest that high intensity statin regimens are associated with poorer treatment adherence when compared to lower intensity regimens. Hence, more robust studies are required to establish this association. As recommended by the 2013 ACC/AHA, 2016 ESC and several other clinical guidelines, clinicians and pharmacy managers should regularly monitor statin therapy adherence.</p