Factors Affecting Suboptimal Adherence to bDMARDs Among Patients With RA

Treatment adherence to prescribed biologic disease-modifying anti-rheumatic drugs (bDMARDs) may be low among patients with rheumatoid arthritis (RA), and greater knowledge of factors influencing these suboptimal adherence rates is necessary,

according to results of a retrospective observational cohort study published in Rheumatology International.

While treatment with biological therapies is proven effective among patients with RA, compliance with prescribed regimens remains low. Researchers assessed the influence of demographic and clinical factors on treatment adherence among patients with RA.

Data were taken from a disease-specific database of two rheumatology clinics in Bulgaria. Patients aged at least 18 years with a diagnosis of seropositive RA who initiated biologic treatment from October 2014 to May 2017 were included in the study.

Duration of study follow-up was 36 months, with clinical evaluations and questionnaires to assess treatment adherence performed at baseline, 6, 12, 24, and 36 months. Disease activity was measured using the Disease Activity Score-28 erythrocyte sedimentation rate (DAS28-ESR) and physical function/disability was measured by the Health Assessment Questionnaire Disability Index (HAQ-DI).

Univariate and multivariate logistic regression were used to determine potential predictors of treatment adherence.

A total of 179 patients were included in the study. The overall compliance rate was 89.7% in the first year, 76% in the second year, and 64% in the third year among patients taking bDMARDs. The lowest compliance rate (50%) was found among patients taking infliximab. Patients in other medication subgroups demonstrated similar compliance rates (64-70%). Thirty-six percent (63/179) of patients ultimately discontinued the study.

Median DAS28-ESR values were higher at baseline and 24 months among patients that discontinued treatment (both P <.001), while there was a significant decrease in these values between baseline and 24 months among the overall cohort.

The researchers noted that factors such as gender, specific type of biological medication, and treatment with combination methotrexate and a biologic/monotherapy with bDMARDs negatively affected DAS28-ESR values at all follow-up time points.

Median DAS28-ESR scores were higher among patients previously treated with bDMARDs at the 6-, 12-, and 24-month time points.

Over the follow-up period there was a decrease in self-reported HAQ-DI values, indicating an improvement in patients’ functional capacity between 0 and 6 months (P <.001), 6 and 12 months (P <.001), and between 24 and 36 months (P =.002).

Results of multivariate analyses indicated that only DAS28-ESR scores (odds ratio [OR], 1.174; 95% CI, 1.174-2.362) and HAQ-DI scores (OR, 2.803; 95% CI, 1.428-5.503) were found to be possible significant predictors of treatment adherence throughout the entire study period.

This study was limited by its reliance on patient reports and verified prescription refills to assess treatment adherence. Adherence may have been overestimated by less compliant patients due to self-reporting.

The study authors concluded, “It is important to identify the predictors that impact the patient’s agreement with the recommended treatment. Thereby, we can better control the disease activity, influence the course of rheumatoid arthritis and prevent later

disease complications.”