Background Dactylitis, is observed in approximate 30% of patients spodnyloarthritis (SpA),with the highest frequency in psoriatic arthritis (PsA).SpA features complicate inflammatory bowel diseases (IBD) in at least one third of the cases.The frequency of dactylitis in IBD-SpA has been assessed in a few open studies with conflicting results^1,2.

Objectives Primary end point: To compare the frequency of dactylitis in a clinical series of patients with IBD-associated SpA (IBD-SpA) compared with other types of SpA. Secondary end point: to evaluate the frequency of articular and extra-articular manifestations of IBD-associated SpA compared to controls.

Methods 24-month case-control study. Case patients: all consecutive patients meeting the ASAS criteria for both axial and peripheral SpA,and with a diagnosis of Crohn's disease (CD) or ulcerative colitis (UC) certified by the gastroenterologist. Controls: the 2 consecutive patients with other SpA (ASAS criteria) observed after the case patient during the same time interval. Dactylitis diagnosis was accepted if observed at visit or if certified in the past by a rheumatologist working in our center.Patients were followed by the same rheumatologist,and follow-up visits were scheduled at baseline and every 4 months.All clinical and laboratory data were recorded in a computed patients'chart. The date of the last visit constituted the end of the follow-up.

Results Case patients:88 IBD-SpA patients, 29 UC and 59 CD, 42 F/46M, mean age 47.66±15.09 ys, 10 (11.3%) B27+.Mean IBD duration was 60.05±54.66 months. Controls: 176 SpA patients, 98 PsA, 46 AS, and 32 non-radiographic axial SpA (nrx-AxSpA); 89F/87M, mean age 46.35±24.88 ys. 70 (40.7%) B27+, mean disease duration of 43.21±28.34 months. In IBD-SpA axial involvement was observed in 46 (52%) patients, peripheral in 29 (33%) and mixed in 13 (15%). Peripheral SpA was oligoarticular (≤4 joints involvement) in 26/29 (90%) patients and polyarticular in 3 (10%). Psoriasis (Pso) was associated in 14/88 (16%) of the cases. Dactylitis was recorded in 4 (4.5%) of IBD-SpA patients and in 30 (17.4%) of controls with a significant statistical difference (p=0.018). Dactylitis was recorded in only 2/74 (2.7%) IBD-SpA patients without Pso (p vs controls=0.010).Also enthesitis prevalence was significantly lower in IBD-SpA occurring in 16/88 (18.1%) patients and in 78/176 (44.3%) controls (p=0.004). Enthesitis frequency was significantly higher in 14 IBD-SpA patients associating Pso (28.5%) compared with the remaining 74 cases (16.2%) (p=0.012). Dactylitis occurred in 2/29 (6.9%) and in 2/59 (3.38%) patients with UC and CD, respectively. Anterior uveitis was recorded in 3 (3.4%) IBD-SpA patients and in 26 (14.7%) controls (p=0.02).

Conclusions Dactylitis and enthesitis were significantly lower in IBD-SpA patients compared to other SpA. As reported³, Pso was frequent in our cohort of IBD-SpA,and its coexistency significantly increased the frequency of enthesitis and to a lesser extent of dactylitis.Anterior uveitis was significantly less frequent in IBD-SpA compared to controls.

1. Salvarani C, et al. Scand J Rheumatol 2001;

2. Alamino RP, et al. J Rheumatol.2011;

3. Li W-Q, et al. Ann Rheum Dis 2013.

Disclosure of Interest None declared