The Relationship Between Function and Disease Activity as Measured by the HAQ and DAS28 Varies Over Time and by Rheumatoid Factor Status in Early Inflammatory Arthritis (EIA). Results from the CATCH Cohort§

Tristan A Boyd1, A Bonner2, C Thorne3, G Boire4, C Hitchon5, B.P Haraoui6, E.C Keystone7, V.P Bykerk7, 8, J.E Pope*, 1, 9Author Comment: for CATCH Investigators

1 Department of Internal Medicine, Schulich School of Medicine & Dentistry, University of Western Ontario, Canada
2 Department of Mathematics and Statistics, McMaster University, Canada
3 Southlake Regional Health Centre, Newmarket, Canada
4 Rheumatology Division, Universite de Sherbrooke, Canada
5 Arthritis Centre, University of Manitoba, Canada
6 Rheumatic Disease Unit, Institut de Rhumatologie, Montreal, Canada
7 Rheumatology, Mount Sinai Hospital, University of Toronto, Canada
8 Rheumatology, Brigham and Women’s Hospital, Harvard University, Canada; and now Hospital for Special Surgery, NY, USA
9 Rheumatology, St. Joseph’s Health Care, London, Ontario, Canada

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© Boyd et al.; Licensee Bentham Open.

open-access license: This is an open access article licensed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted, non-commercial use, distribution and reproduction in any medium, provided the work is properly cited.

* Address correspondence to this author at the 268 Grosvenor St., London, ON N6A 4V2 Canada; Tel: 519 646 6332; Fax: 519 646 6334; E-mail:
§ This study has been presented as an abstract at ACR and Canadian Rheumatology Association meeting.



To investigate the relationship between function and disease activity in early inflammatory arthritis (EIA).


Canadian Early Arthritis Cohort (CATCH) (n=1143) is a multi-site EIA cohort. Correlations between the Health Assessment Questionnaire Disability Index (HAQ) and DAS28 were done at every 3 months for the first year and then at 18 and 24 months. We also investigated the relationship between HAQ and DAS28 by age (<65 versus ≥65) and RF (positive vs negative).


Mean HAQ and DAS28 scores were highest at the initial visit with HAQ decreasing over 24 months from a baseline of 0.94 to 0.40 and DAS28 scores decreasing from 4.54 to 2.29. All correlations between HAQ and DAS28 were significant at all time points (p<0.01). The correlations between HAQ and DAS28 were variable over time. The strongest correlation between HAQ and DAS28 occurred at initial visit (most DMARD naive) (n=1,143) and 18 months (r=0.57, n=321) and 24 months (r=0.59, n=214). The baseline correlation between HAQ and DAS28 was significantly different than correlations obtained at 3, 6, and 12 months (p=0.02, 0.01, and 0.01, respectively). Age did not change the association between HAQ and DAS28 {<65 years old (r=0.50, n=868) versus ≥65 (r=0.48, n=254), p=0.49}. The correlation between HAQ and DAS28 was stronger with RF+ patients (r=0.63, n=636) vs RF negative (r=0.47, n=477), p=0.0043


Over 2 years in EIA, HAQ and DAS both improved; correlations at time points were different over 2 years and RF status affected the correlations.

Keywords: : HAQ, early RA, disease activity, DAS, cohort, correlation, longitudinal..