The Osteoarthritis Quality of Life scale (OAQoL) is an osteoarthritis-specific measure developed in the United Kingdom by a needs-based approach. This study describes the adaptation and validation of this English scale into French.
The OAQoL was translated into French by a dual-panel technique followed by cognitive debriefing interviews. Internal consistency was assessed by the Cronbach α. Construct validity was tested by exploratory and confirmatory factor analyses and by convergent and divergent correlations with other patient-reported outcome measures by the Spearman rho (ρ). Reliability was explored by Spearman rho as well as the Bland and Altman method for the total score and Cohen's kappa for each item score.
Cognitive debriefing revealed the French OAQoL to be clear, relevant and comprehensive. The Cronbach α was 0.91. Exploratory factor analysis extracted 4 groups of items. After eliminating 4 items, confirmatory factor analysis of the remaining 18 items confirmed higher intra-factor than inter-factor correlations. The expected convergent and divergent correlations were observed. Test-retest reliability was good (ρ 0.93) and was confirmed by Bland and Altman analysis; most items (12/18) had kappa values from 0.61 to 0.80.
The French OAQoL is an easy-to-use 18-item questionnaire with good content and construct validity to assess the impact of osteoarthritis on quality of life for French-speaking patients.