Treatment adherence in systemic sclerosis: A cross-sectional study

Treatment adherence is an important medical and pharmaco-economical phenomenon, influenced by multiple variables. Treatment adherence in systemic sclerosis (SSc) has been poorly studied.

The aim of the present study was to assess treatment adherence in SSc patients and to identify factors associated with good and poor adherence.

We conducted a monocentric, cross-sectional, observational study. Treatment adherence was evaluated by the Compliance Questionnaire of Rheumatology (CQR). The necessity of treatment and concerns about treatment were investigated using the Beliefs about Medicines Questionnaire-Specific (BMQ-S). The Illness Perception Questionnaire-Revised (IPQ-R) assessed illness perceptions. Disease-related characteristics were collected retrospectively.

A total of 66 patients were enrolled in this study. Of these, 47 (71.2%) had a weighted CQR score of ≤80% ("poor adherence") and 19 (28.8%) had a weighted CQR score of >80% ("good adherence"). No significant relationship between demographic, clinical or psychological factors and overall adherence could be found, except with the IPQ subscale "timeline acute/chronic" (p = 0.042). Our patient population estimated the necessity of their medication high (mean necessity score 20.5), with moderate concern beliefs (mean concern score 15.1). Subjective adherence, as self-reported by patients, was high.

This study demonstrated low treatment adherence rates in SSc patients. We could not identify demographic, clinical or psychological factors associated with treatment adherence, except with the IPQ subscale "timeline acute/chronic". This suggests a correlation between poor adherence and the belief that the disease will be chronic without improvement over time. Symptom relief was an important motivating factor for taking medication. The treatment necessity was scored higher than treatment concerns, but the necessity beliefs were not associated with adherence.