Baecke questionnaire validity in knee osteoarthritis: A cross-sectional study

The Baecke Habitual Physical Activity Questionnaire (BHPAQ) has been widely used to assess physical activity levels in adults and older populations. However, the construct validity of this instrument was never tested in individuals with knee osteoarthritis (KOA). The present study aimed to assess the construct validity of the BHPAQ in the KOA population.

A cross-sectional study was conducted following the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines. A sample of 80 participants met the American College of Rheumatology (ACR) criteria for KOA. In the first session, demographic data were collected, and participants performed the 40m fast-paced walk test (40m FPWT). The WOMAC and BHPAQ were applied, and an accelerometer was used, returned after a 7-day period. Construct validity was assessed using the COSMIN checklist, with >75% of predefined hypotheses required for BHPAQ validity. These hypotheses were based on WOMAC domains and accelerometer outcomes.

Of the 80 participants in the final sample, 40 (or 50%) were women, and their average age was 59.5±8.40 years. To determine construct validity, the Spearman's correlation coefficient was computed. Only four out of ten (40%) of the predefined hypotheses were confirmed by the BHPAQ. Limitations include not assessing participants' educational level and not capturing activities undetectable by the accelerometer.

The BHPAQ demonstrated low construct validity for assessing the level of physical activity in the population with KOA. For this reason, its use is not recommended for research or clinical practice.