Objective: Although medication adherence (MA) contributes to therapeutic outcome in systemic sclerosis (SSc), research data are scarce. Factors influencing MA in SSc are hardly known.
Method: We conducted a monocentric, cross-sectional study on 85 patients with SSc at the University of Lübeck, Germany, using the Compliance Questionnaire of Rheumatology as the main measurement tool of MA. We also used the Scleroderma Health Assessment Questionnaire, Illness Perception Questionnaire - Revised, Health Literacy Questionnaire, Lübeck Medication Satisfaction Questionnaire (a novel instrument created for this study), and patients' demographic and clinical data, to find factors contributing to MA.
Results: Good MA was seen in 51.8% of patients. MA was positively associated with therapy satisfaction (p < 0.001), modified Rodnan Skin Score (p = 0.032), age (p = 0.025), intake of micronutrients (p = 0.033), number of prescribed drugs (p = 0.014), and some dimensions of health literacy. Negative associations were found for patients with weight loss attributed to SSc (p = 0.009) and the perception that the disease is caused by the patient's personality (p = 0.011) or emotional state (p = 0.037).
Conclusion: Although most SSc patients display good MA, non-adherence remains a major problem. Patients should be assessed for non-adherence. The factors affecting MA identified herein could help to improve therapeutic outcomes.