Background/Purpose: Dactylitis is a particular feature shared across the several phenotypical forms of spondyloarthritis (SpA), part of the classification criteria. There are only few data available about incidence of dactylitis in early stage of SpA, and factors associated with dactylitis.

Aim

To study, over 5 years in the DESIR cohort, the prevalence and incidence of dactylitis and to look at the factors associated with presence/incidence of dactylitis.

Methods: DESIR is a prospective observational cohort of patients with recent onset (less than 3 years) inflammatory back pain, beginning before 50 years, suggestive of axial SpA, All available factors in the database (clinical, biological, imaging and medico economic) were compared between patients with and without past or present dactylitis at 5 years (for categorical variables : odds-ratio +/- 95% CI and chi-square/Fisher tests, for continuous variables : unpaired t-tests / Mann-Whitney) , by uni and then multivariate analysis (logistic regression). Baseline factors associated with new cases of dactylitis occurrence were also analyzed. Significance: p less than 0.05.

Results: After 5 years, 138 cases of dactylitis were recorded in 480 patients with complete follow-up : prevalence 28.75 % [CI 95% 24.75-32.75]. At 5 years, dactylitis was significantly associated (multivariate analysis) with : Achilles enthesitis (OR : 3.3), history of psoriasis (OR: 3.9), cumulative number of ASAS criteria (OR: 7.2), modified New York criteria fulfillment (OR: 0.35), DMARD use (OR: 2.7) and elevated CRP (OR:0.9).

Incident new cases were recorded in 41 patients, with an estimated incidence of 1.7/100 patient-years. These incident cases were significantly associated with some baseline factors (multivariate analysis) : female gender (OR: 3.6), psoriasis (OR:3.4), HAQ over median (OR: 5.7), IL-31 levels over median (OR: 1.04), ASQol over median (OR: 0.84), IL-6 over median (0.83).

Conclusion: In the DESIR cohort of patients suspected for early SpA, dactylitis presence or history is recorded in 28.7 % of the cases at 5 years, with an estimated incidence of 1.7/100 p-y over 5 years. It is an early feature associated with peripheral involvement, psoriasis, more frequent use of DMARDs, but with less structural damage. Female gender and psoriasis are associated with incidence of new cases of dactylitis over 5 years in this population.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/dactylitis-occurrence-in-early-spondyloarthritis-five-years-data-from-a-french-national-prospective-cohort/