The Health Assessment Questionnaire (HAQ) Disability Index is the most frequently used and validated measure of physical function for patients with rheumatoid arthritis (RA).1 Various translated versions of this questionnaire have been used in clinical research in the Netherlands. In 2007, a standardised translation, the Dutch consensus HAQ, was introduced and a letter detailing its development appeared in this journal.2 The Dutch DREAM registry,3 a multicentre observational cohort study that monitors RA patients undergoing different treatment regimens, soon adopted the consensus HAQ.
Oude Voshaar, A. H., ten Klooster, P. M., Vonkeman, H. E., Kievit, W., van Riel, P. L. C. M., & van de Laar, M. A. F. J. (2013). Measurement bias in different versions of the Dutch Health Assessment Questionnaire Disability Index. Annals of the rheumatic diseases, 72(12), 2050-2051. https://doi.org/10.1136/annrheumdis-2013-203512