Field testing and clinical validation of the mSQUASH to measure physical activity in patients with Sjögren's disease.

Objectives: Regular physical activity is recommended in patients with rheumatic diseases. In order to uniformly measure physical activity, our aim was to perform field testing of the modified Short QUestionnaire to ASsess Health enhancing physical activity (mSQUASH) in Sjögren's disease (SjD), together with other rheumatic diseases, and to investigate construct validity and test-retest reliability of the mSQUASH in patients with SjD.

Methods: The mSQUASH was tested by conducting semi-structured interviews in patients with SjD (n=10), systemic lupus erythematosus (n=10), giant cell arteritis/polymyalgia rheumatica (n=10) and axial spondyloarthritis (n=13) to check for understandability, interpretation and relevance.

The mSQUASH is a feasible and valid measurement tool to uniformly assess daily physical activity in patients with rheumatic diseases.

Background: The modified Short QUestionnaire to ASsess Health-enhancing physical activity (mSQUASH) was originally developed and validated in Dutch patients with axial spondyloarthritis (axSpA). To support world-wide distribution, applicability and comparability of measuring physical activity, our aim was to perform translation and cross-cultural adaptation of the mSQUASH into English, field testing in other rheumatic diseases and clinical validation in patients with axSpA.

Methods: The Dutch mSQUASH was translated into English according to forward-backward Beaton protocol.