Pharmaceutical economics & health policyReview articleMeasurement and Rates of Persistence With and Adherence to Biologics for Rheumatoid Arthritis: A Systematic Review
Introduction
Rheumatoid arthritis (RA) is a chronic and progressive inflammatory arthritis that if left untreated may result in severe joint damage and loss of function.1 Biologic treatments have been assessed in individuals with RA.2 Although NSAIDs, conventional disease-modifying antirheumatic drugs (DMARDs) such as methotrexate and sulfasalazine, and corticosteroids have been the cornerstones of therapy for many years, newer DMARD biologics such as the anti–tumor necrosis factor (TNF)-α agents have been associated with RA remission—the least amount of disease activity by tender and swollen joint counts (Table I).2 Hence, patients and physicians have been willing to assume risks such as infections that may accompany the use of these treatments.2
Poor adherence due to nonclinical factors such as inefficacy, adverse events, or remission, however, may undermine the potential therapeutic benefits of biologics by contributing to treatment failure, progression of disease, and the need for more aggressive treatment.3 Poor adherence further strains already limited health care resources; incomplete treatment provides few or no benefits, and the costs of even partial treatments are high given the expense of the biologics.4 Nonadherence also raises concerns for the insurers and payers responsible for the costs of these agents and the medical costs of disease progression and more aggressive treatment. Therefore, it is clinically and economically important to assess persistence with and adherence to biologic regimens in the RA population.
Methods for measuring persistence with and adherence to oral medications are well established because the majority of oral medications have predictable daily dosing schedules.5, 6, 7, 8 Biologics, however, have complex dosing schedules, and dosages and frequency of dosing are often altered during treatment (Table I). The objective of this review was to summarize the methods used to measure, and the reported rates of, persistence with and adherence to biologic regimens in patients with RA.
Section snippets
Methods
A literature search was conducted to identify studies that measured rates of persistence with and adherence to biologic regimens in patients with RA in clinical practice. In general, the term persistence refers to continuation of drug use for an overall duration of drug therapy (eg, 12 months), and adherence refers to the extent of drug use during a period of persistence (eg, 12 weeks).9 Continuation rate, retention rate, and drug survival are measures of persistence; mean medication possession
Results
Fifty-two studies met the selection criteria. Although all were original studies, 2 were published in letter format.10, 11 Table II summarizes the main characteristics of the included studies.
Discussion
Of the studies included in this review, several assessed adherence to biologics in patients with RA, but most assessed only persistence. Persistence is an important measure that adds the dimension of time to understanding the patterns of use of pharmacotherapies. It usually represents the time over which a patient continues administration based on prescription claims, or the time from the initial fill of the medication until the patient discontinues refills. However, adherence also helps to
Conclusions
Persistence with and adherence to biologic regimens in patients with RA in clinical practice has been measured in multiple studies; however, the methods for measuring the 2 end points have been poorly defined and/or inconsistent from study to study. Most of the findings included in the present review were based on registry data from Europe, with relatively few studies from the United States. The findings highlight the need for better methodologies to track persistence with and adherence to
Acknowledgments
This study was supported by an investigator-initiated research grant from Abbott Laboratories Inc, Abbott Park, Illinois. Dr. Doshi has served on the health economics advisory boards of Amgen Inc, Thousand Oaks, California, and Bristol-Myers Squibb Company, New York, New York.
The authors have indicated that they have no other conflicts of interest with regard to the content of the article. Dr. Blum was responsible for the study design, literature search, data abstraction, interpretation, and
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