Abstract
INTRODUCTION: Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease, for which the introduction of injectable treatments has had a major impact on quality of life directly related to the disease. The purpose of this descriptive study was to evaluate the usability of a new autoinjector, intended for methotrexate self-administration, based on the device's design and instructions for use (IFU). METHODS: This multicenter trial included three user groups: a group of patients with established RA subdivided into two groups according to their hand disability, and a group of caregivers or nurses. Each subject performed three simulated injections with a water-filled device on a foam pad. The first injection was made just after reading the IFU without further instructions (first phase). The second phase consisted of two injections made after explanations provided upon request of the subject in an optimum environment and in a "worst-case" home environment. The usability of the autoinjector was assessed by a questionnaire (success: ≥75% of positive responses) and by a score card reflecting injection performances (success: execution of ≥75% of handling steps). RESULTS: Forty-two subjects were enrolled in the study. During the first phase, the great majority of subjects succeeded in the usability questionnaire (90.5%) and in the injection performance (95.2%) with no major differences between the user groups. In the Second phase, all subjects from all three user groups succeeded in the usability questionnaire and had a positive rate of device handling, regardless of the environment and of the user group. No safety concerns were raised during the study. CONCLUSIONS: This study found a very high level of usability and subject acceptance of the autoinjector, intended for methotrexate self-administration, regardless of the hand disability and environmental conditions. FUNDING: Nordic Group. TRIAL REGISTRATION: EudraCT reference number: 2014-A0141245.