Predictors of Treatment Adherence Assessed in Rheumatic Diseases

Patterns of treatment adherence for patients with rheumatoid arthritis (RA), psoriatic arthritis (PsA), and ankylosing spondylitis (AS) are dependent on treatment beliefs more than disease-related factors, according to a cross-sectional study published in Rheumatic and Musculoskeletal Diseases Open.

Researchers of the ALIGN study analyzed patients who had immune-mediated inflammatory diseases for beliefs in medication and therapy usage, patient demographic characteristics, and disease-related factors to determine adherence prediction models. Self-administered surveys included the Beliefs about Medicines Questionnaire, Brief Illness Perception Questionnaire, and Morisky Medication Adherence Scale, as well as investigator-reported patient demographic information, disease characteristics, and treatment-related variables.

Of the 3390 patients included in this subset of the study, 1943 had RA, 635 had PsA, and 812 had AS. The patients in the RA group were 82.2% women, 70% white, and had an average age of 54.8 years. The patients in the PsA group were 46.3% women, 90.1% white, and had an average age of 50.7 years. The patients in the AS group were 28.6% women, 68.8% white, and had an average age of 42.5 years.

Patients with RA had the longest mean current treatment duration at 5.3 years, and 58.1% received conventional synthetic disease-modifying antirheumatic drug (csDMARD) therapy. Patients with PsA had a mean current treatment duration of 4.1 years with a fairly even distribution between csDMARD therapy, tumor necrosis factor inhibitor (TNFi) monotherapy, and csDMARD/TNFi combination therapy. Patients with AS had a mean current treatment duration of 3.8 years, and 46.1% received TNFi monotherapy.

Overall, patients taking TNFi with or without concomitant csDMARD therapy had higher treatment adherence than csDMARD and nonsteroidal anti-inflammatory drugs. Higher values on the Beliefs about Medicines Questionnaire-Specific Necessity questions were associated with higher treatment adherence for all 3 disease groups. Predicative adherence models included the variables of type of treatment, age, and medication necessity beliefs for all 3 immune-mediated inflammatory diseases. Simple models were specifically created for each disease type in the hope of helping to identify patients at risk for low treatment adherence.

Limitations of this study include lower statistical power for the PsA and AS groups due to smaller sample sizes, differences in demographic data between the groups, a disproportion in the number of white patients compared with the general population, a subjective judgment of disease activity, and treatment adherence being self-reported.

The researchers concluded that “higher treatment necessity beliefs were more consistently associated with medication adherence than disease-related or medication-related factors.”

This study was supported by AbbVie and other pharmaceutical companies. Please refer to reference for a complete list of authors’ disclosures.

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Reference

Smolen JS, Gladman D, McNeil HP, et al. Predicting adherence to therapy in rheumatoid arthritis, psoriatic arthritis or ankylosing spondylitis: a large cross-sectional study. RMD Open. 2019;5(1):e000585.