Polypharmacy, Drug-Drug Interactions, and Adverse Drug Reactions among Systemic Sclerosis Patients: a Cross-Sectional Risk Factor Study.

ObjectivesPolypharmacy, drug-drug interactions (DDI) and related adverse drug reaction (ADR) are understudied in SSc. The aim of this work was to determine the prevalence and determinants of DDI and ADR in a real-life prospective cohort of SSc patients.MethodsWe performed a retrospective analysis of the drug prescriptions of SSc patients admitted to the daily scleroderma clinic between January 2020 and April 2022. DDI were identified using 2 prescription analysis applications, and adjudicated related ADRs occurring during a one-year follow-up were reported. Risk factors for DDI and ADR were identified using multivariate analysis.ResultsOne hundred and eight SSc patients were included. The median number of medications per patient was 6 [4-9]. Seventy-one (65.7%) patients had 5 or more medications, and 23 (21.3%) had 10 or more. Seventy-two (66.7%) patients had DDIs on their prescriptions at inclusion. Patients with DDIs had more medications than patients without DDIs (7 [5-10] versus 3 [2-5], p<0.0001). Six (8.3) patients experienced ADRs during the one-year follow-up. Patients with ADRs had more medications (14 [10-18] versus 7 [5-10] p<0.001) and more DDIs (12 [7-32] versus 3 [1-6]; p<0.001) than patients without ADRs. Multivariate analysis confirmed that the number of prescribed medications was independently positively associated with DDIs (OR: 2.25 [1.52-3.32], p<0.0001) as well as with ADRs (OR: 1.68 [1.17 - 2.40], p<0.01).ConclusionsSSc patients are significantly exposed to polypharmacy, DDIs and related ADRs, particularly in cases of severe illness, and especially if 5 or more medications are prescribed.