Validation of the SQUASH physical activity questionnaire using accelerometry: The NEO study

Sietse E S Terpstra; Lotje A Hoogervorst; Jeroen H P M van der Velde; Renée de Mutsert; Lotte A van de Stadt; Frits R Rosendaal; Margreet Kloppenburg

doi:10.1016/j.ocarto.2024.100462

Validation of the SQUASH physical activity questionnaire using accelerometry: The NEO study

Osteoarthr Cartil Open. 2024 Mar 18;6(2):100462. doi: 10.1016/j.ocarto.2024.100462. eCollection 2024 Jun.

Authors

Sietse E S Terpstra^{1

2}, Lotje A Hoogervorst^{3

4}, Jeroen H P M van der Velde², Renée de Mutsert², Lotte A van de Stadt¹, Frits R Rosendaal², Margreet Kloppenburg^{1

2}

Affiliations

¹ Department of Rheumatology, Leiden University Medical Center, the Netherlands.
² Department of Clinical Epidemiology, Leiden University Medical Center, the Netherlands.
³ Department of Orthopaedics, Leiden University Medical Center, the Netherlands.
⁴ Department of Medical Decision Making, Leiden University Medical Center, Leiden, the Netherlands.

Abstract

Objective: To investigate the construct validity of the SQUASH (Short QUestionnaire to ASsess Health-enhancing physical activity).

Design: This is a cross-sectional analysis using baseline measurements from middle-aged participants in the Netherlands Epidemiology of Obesity (NEO) study. The SQUASH consists of questions on eleven physical activities investigating days per week, average duration per day and intensity, leading to a summed score in Metabolic Equivalent of Task hours (MET h) per week. To assess convergent validity, a Spearman's rank correlation between SQUASH and ActiHeart was calculated. To assess extreme group validity, three groups expected to differ in SQUASH total physical activity outcome were compared. For discriminative validity, a Spearman's rank correlation between SQUASH physical activity and participant height was investigated.

Results: SQUASH data were available for 6550 participants (mean age 56 years, 44% men, mean BMI 26.3, 15% with knee OA, 13% with hand OA). Median physical activity (interquartile range) was 118 (76; 154) MET h/week according to SQUASH and 75 (58; 99) according to ActiHeart. Convergent validity was weak (rho = 0.20). For all three extreme group comparisons, a statistically significant difference was present. Discriminative validity was present (rho = 0.01). Compared with the reference quintile, those with a discrepancy SQUASH > ActiHeart and SQUASH < ActiHeart were relatively younger and more often male.

Conclusions: The construct validity of the SQUASH seems sub-optimal. Physical activity reported by the SQUASH was generally higher than reported by ActiHeart. Whether the differences between SQUASH and ActiHeart are e.g. due to different underlying domains, limitations to our study, or reflect true differences needs further investigation.

Keywords: Accelerometer; Epidemiology; Patient reported outcomes; Physical activity; Quality of life.