Background Previous studies have reported medication adherence ranging from 49.5% to 98.5% in patients with rheumatoid arthritis (RA) 1. Adherence to TNFi has been estimated to be 59%2. Non-adherence has been associated with poorer health outcomes, such as physical disability and increased need for health services.
Objectives The aim of the study was to analyse adherence to self-injectable biologic disease-modifying antirheumatic drugs (bDMARDs), conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) and glucocorticoids in Finnish RA patients using their first bDMARDs.
Methods RA patients starting their first bDMARD in 2007–2011 were identified from the National Register for Biologic Treatment in Finland (ROB-FIN). Restriction to the patients with available baseline data and at least 360 days follow-up with their first bDMARD was made. Data on prescribed medication was recorded in ROB-FIN while medication claims were retrieved from the register of the Social Insurance Institution of Finland. The proportion of days covered (PDC) during a 360-day period was calculated to define adherence. Patient was considered adherent if PDC was ≥80%.
Results Fifty-two percent (n=424) of the 823 patients remained on the first bDMARD and were followed for at least 360 days. Forty-three percent of them (205) were adherent to all prescribed anti-rheumatic medication. CsDMARDs were prescribed to 372 patients of which 53% (196) were adherent while 5% (20) claimed no cdDMARD at all. Methotrexate was the most common csDMARD and was prescribed to 281 patients. The proportions of patients adherent to methotrexate and patients who claimed no methotrexate at all were 60% (170) and 9% (26), respectively. Self-injectable bDMARDs were prescribed to 319 of which 59% (187) were adherent and 8% (25) did not claim any of the prescribed bDMARD. Mean PDC for csDMARDs, methotrexate and self-injectable bDMARDs were 73%, 74% and 74%, respectively.
Conclusions Less than half of the RA patients using bDMARDs were adherent to their antirheumatic medication. However, the current data measures only the medication claims instead of actual use. Moreover, the high proportion of patients lost to follow-up may cause bias to the results.
Pasma A, van't Spijker A, Hazes JMW, et al. Factors associated with adherence to pharmaceutical treatment for rheumatoid arthritis patients: a systematic review. Semin Arthritis Rheum. United States; 2013 Aug;43(1):18–28.
Fidder HH, Singendonk MMJ, van der Have M, et al. Low rates of adherence for tumor necrosis factor-alpha inhibitors in Crohn's disease and rheumatoid arthritis: results of a systematic review. World J Gastroenterol. China; 2013 Jul;19(27):4344–50.
Acknowledgement ROB-FIN has received restricted financial support from Abbvie, Roche, MSD and Pfizer.
Disclosure of Interest None declared
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