Has the baseline severity of inflammatory polyarthritis diminished over time?

Janet Diffin, Mark Lunt, Tarnya Marshall, Jacqueline Chipping, Deborah Symmons, Suzanne Verstappen

Research output: Contribution to conferencePosterpeer-review

Abstract

Background: Previous research has suggested that the severity of RA has decreased over time. This study examines the pattern of disease severity in patients with inflammatory polyarthritis (IP) at time of registration into the Norfolk Arthritis Register (NOAR). Methods: NOAR is a primary-care-based cohort of adults with recent onset IP (≥2 swollen joints lasting for >4 weeks). Disease related variables assessed at baseline include 51- swollen and tender joint count and the Health Assessment Questionnaire (HAQ). Blood is collected and C—reactive protein (CRP), Rheumatoid Factor (RF), and Anti-Citrullinated Peptide Antibodies (ACPA) are measured. The DAS28 (Disease Activity Score) is calculated using CRP level. In this study, patients with a symptom duration of <2 years at baseline were grouped into four cohorts depending on the NOAR recruitment phase: (1) 1990–1994; (2) 1995–1999; (3) 2000–2004; (4) 2005–2009. Three sub-samples were also evaluated: (i) referred first to NOAR by their general practitioner; (ii) Disease Modifying Anti-Rheumatic Drug (DMARD) naive at baseline; (iii) met the ACR/EULAR 2010 RA criteria at baseline. Linear or median regression analyses, depending on the distribution of the dependent variable, were conducted to examine baseline HAQ or DAS28 scores over time. A quadratic term for calendar year of assessment by NOAR was included as a predictor and if significant, cohort was included to examine if the rate of change in scores over time differed between cohorts. Confounders included gender, RF and ACPA positivity, and age at symptom onset. Results: 3045 patients were evaluated within the total sample (Table 1). The calendar year of assessment was a significant predictor of lower DAS28 scores over time for the total sample (adjβ = –0.0007, 95% CI –0.001, –0.0001), and each sub-sample. Within the total sample, and the DMARD naive sub-sample, there was a significant effect of ‘Cohort', and a significant ‘Calendar year by Cohort' interaction. The calendar year of assessment was not a significant predictor of HAQ scores for the total sample (adjβ = 0.0002, 95% CI –0.0002, 0.001). Conclusions: Whilst baseline disease activity has decreased over time, there has been no change in levels of functional disability.
Original languageEnglish
DOIs
Publication statusPublished - 2013
EventThe British Society for Rheumatology (BSR) Annual Conference - Birmingham, United Kingdom
Duration: 23 Apr 201325 Apr 2013

Conference

ConferenceThe British Society for Rheumatology (BSR) Annual Conference
CountryUnited Kingdom
CityBirmingham
Period23/04/201325/04/2013

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