Background In the early stages of Rheumatoid Arthritis (RA), adherence to the prescribed drug treatment is important to prevent irreversible joint damage. However, medication adherence rates in RA patients can be improved. To explain the suboptimal adherence in RA patients, factors that influence adherence behavior should be elucidated. These factors were last reviewed in 1982. Since then, treatment strategies for RA have changed, which means that nowadays different factors might play a role.
Objectives To review adherence rates reported in the literature, to identify factors that are associated with adherence, to review the strength of the association between these factors and adherence and to cluster the identified factors according to the Health Belief Model (HBM) (1).
Methods PubMed, PsycINFO, EMbase and CINAHL databases were systematically searched for relevant articles published up to February 2011. Articles were included if they addressed medication adherence, described factors related to adherence, used a reproducible definition or validated instrument to measure adherence and provided a statistical measure to reflect the strength of the association between adherence and factors. Their methodological quality was assessed using a quality assessment list for observational studies derived from recommendations from Sanderson, Tatt and Higgins (2).
Results Of the 1479 studies that were found, only 18 were eligible. Adherence rates ranged between 49.5% and 98.5%. 71 factors were identified and grouped into 7 categories: disease features, medication features, health system factors, knowledge about the disease, knowledge and satisfaction about medication, interpersonal factors and intrapersonal factors. These categories were assigned to the HBM (figure 1.). Most factors had been evaluated by multiple studies, but these had yielded conflicting results on associations between factors and adherence. The only 2 factors that had a consistent influence on adherence behaviour were the relationship between patient and healthcare provider and the belief that it is necessary to take the medication.
Conclusions The 2 factors that are consistently associated with adherence are the relationship between patient and healthcare provider and the belief that it is necessary to take the medication. However, other factors have either a conflicting or no relationship with adherence. Since research on factors influencing adherence in RA patients has mostly focussed on demographic features and disease futures, future studies should use a theoretical framework to explore the role of interpersonal factors and other relevant determinants of adherence. In addition, the adherence rates reported varied greatly and were difficult to compare. Future studies should therefore adopt a standard for measuring adherence in RA patients, as this would make it easier to compare and interpret results.
Rosenstock IM, Strecher VJ, Becker MH. Social learning theory and the Health Belief Model. Health Education Quarterly. 1988;15(2):175-83.
Sanderson S, Tatt ID, Higgins JPT. Tools for assessing quality and susceptibility to bias in observational studies in epidemiology: a systematic review and annotated bibliograph. International Journal of Epidemiology. 2007;36(3):666-76.
Disclosure of Interest None Declared