Reliability and validity of the Baecke physical activity questionnaire in adult women with hip disorders

BACKGROUND Although physical activity maintenance is important for OA management, it is not clear whether people with OA are more inactive or not. One possible reason is no simple monitoring tool to assess physical activity at the clinic. The aim of this study was to determine the reliability and validity of the Baecke Physical Activity Questionnaire (BQ) in adult women with hip disorders. METHODS Sixty-four patients with unilateral or bilateral hip disorders were recruited from an outpatients clinic at a university hospital in Japan. BQ includes a total of 16 questions classified into three domains: work, sports, and non-sports leisure activity. For test-retest reliability, one BQ was administrated face-to-face, and a second was mailed to participants two weeks later. Test-retest reliability of BQ was assessed using intra-class correlation (ICC) and Bland and Altman method. To determine criterion validity, the correlation between BQ measurements and pedometer-measured step counts was assessed. Correlations between BQ measurements and step counts were assessed using Spearman rank correlation coefficient (rho). RESULTS Analyses were restricted to the 61 patients (53.3 +/- 11.3 years old) who wore the pedometer continuously for 5 days or more. Twenty eight patients had unilateral hip osteoarthritis, 17 patients had unilateral total hip arthroplasty, and 16 patients had hip osteoarthritis and total hip arthroplasty. The mean step count was 6,309 +/- 2,392 steps/day. In analysis for reliability, the value of ICC was 0.84 for work, 0.83 for sports, 0.78 for non-sports leisure activity, and 0.87 total. Bland and Altman analysis showed the step count and BQ total did not differ significantly from 0 with most falling between 0 +/- 1.96 SD. In analysis for validity, there was a significant but low to moderate correlation between step counts and 3 BQ subscales (rho, 0.30-0.49) and a higher correlation between step counts and total score (rho, 0.49). CONCLUSION BQ is a useful monitoring tool for assessing multiple domains of physical activity with acceptable reliability and validity in adult women with hip disorders.