Adherence to biologic therapy - Does it vary with ethnicity?

Abstract

BackgroundPoor adherence to therapy remains a significant barrier to improving clinical outcomes in rheumatic diseases and carries a major financial burden. It has been linked to medication related patient beliefs, which were reported to differ between ethnic groups. Little is known about these variations in biologic therapies cohorts. The purpose of this study was to identify potential determinants of adherence to biologic drugs including an assessment of the influence of beliefs about medicines and compare determinants of adherence between patients of Caucasian versus other ethnicities (OE). Relationship of adherence to disease outcome was further explored. MethodsA prospective survey was undertaken of patients with inflammatory arthritis prescribed self-administered subcutaneous biologic therapies at our centre. Data were collected using a) self reported adherence b) five item compliance questionnaire for Rheumatology (CQR5) and c) Beliefs about Medications questionnaire (BMQ) specific-five items each for necessity and concern scales. The replies were assessed against the disease activity score measured on the day of recruitment to the survey. Results80 patients contributed to the survey. 90% were prescribed TNF inhibitors. 40 patients were of Caucasian origin and 40 belonged to OE-predominantly of South Asian descent (85%). Disease activity score (DAS) was significantly higher in OE patients with 3.7 (standard deviation (SD) 1.3) compared to Caucasian patients with a DAS of 2.9 (1.6) (p = 0.031). Negative beliefs (i.e. higher concern scale scores) about therapy were significantly more prevalent (24/40) (60%) in the OE group compared to the Caucasian cohort (14/40 (35%) (p = 0.043). 17/40 (42.5%) of OE patients were poorly adherent to biologic therapy compared to 12/40 (30%) of Caucasian participants (p = 0.308). Most respondents (68/80, 85%) agreed that their biologic therapies were necessary for their health. Amongst 12/80 (15%) who disagreed, only two were in the non-adherent group. ConclusionTo our knowledge, this is the first study to demonstrate ethnic differences in disease activity score and related negative beliefs regarding subcutaneous biologic therapies in people with rheumatic diseases.

Keywords: Adherence; Anti TNF; Arthritis; Biologics; Ethnicity.