Development and evaluation of disease-specific patient-reported outcome measures questionnaire for polymyalgia rheumatica: validity, reliability, and responsiveness

Abstract

Background
Polymyalgia rheumatica is an inflammatory disease characterized by stiffness and pain around the proximal muscles of both arms and hips and a peak incidence in adults over 50 years of age. The aim of this work was to assess the reliability, validity, and sensitivity to change of a devised self-reported, disease-specific, outcome measures assessment tool for polymyalgia rheumatica. The questionnaire was developed adopting the framework conceptualized in the Food and Drug Administration principles. and the Outcome Measures in Rheumatology (OMERACT) framework for polymyalgia rheumatica.


Results
The questionnaire was completed by 65 polymyalgia rheumatica patients. Assessment of the reliability of the polymyalgia rheumatica-patient-reported outcome measure questionnaire revealed a high standardized alpha (0.641–861). Content construct assessment revealed a significant correlation (p < 0.01) between the European Quality of life - 5 Dimension (EuroQol - 5D) and Health Assessment Questionnaire in relation to both quality of life and functional disability as assessed in the questionnaire. Variation in both quality of life and functional disability in response to therapy showed significant changes (p < 0.01) in relation to the disease activity status.


Conclusions
The developed polymyalgia rheumatica-patient -reported outcome measure questionnaire is a valid and reliable tool for the evaluation of polymyalgia rheumatica patients in standard practice. Based on the attained information, a management strategy tailored to the individual patient’s health-related quality-of-life measures, disease activity status, preferences, risk factors, and any accompanying comorbidities is feasible in standard care management.