OAKHQOL: a new instrument to measure quality of life in knee and hip osteoarthritis

Abstract

Objective: To develop a questionnaire with which to measure quality of life (QoL) in patients with knee and hip osteoarthritis (OA).

Study design and setting: Thirty-two caregivers and 96 OA patients were interviewed individually (using cognitive and face-to-face techniques) and in focus groups. A group of experts working independently at first and then consensually used the interview transcripts to generate a 46-item questionnaire.

Results: Analysis of questionnaires completed by 263 patients with hip or knee OA resulted in the exclusion of three items (two because of low reliability and one because of a low response rate). Principal component analysis revealed four factors: physical activity, mental health, social functioning, and social support. A pain dimension was individualized. Preliminary testing showed the reliability of the five dimensions to be satisfactory (intraclass correlation coefficients: 0.70-0.85), construct validity was adequate when correlated with the SF36 (Spearman correlation coefficients: 0.43-0.75), and discrimination was satisfactory. The osteoarthritis knee and hip quality of life questionnaire (OAKHQOL) consists of 43 items in five dimensions and three independent items.

Conclusion: The OAKHQOL is the first specific knee and hip OA quality of life instrument. Its development followed an a priori structured strategy to ensure content validity. It meets psychometric requirements for validity and reliability.