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.

Keywords: Quality of life, Osteoarthritis, Hip, Knee, Psychometry