Background/Purpose:

Enthesitis reflects inflammation at the insertion of tendons and ligaments into bone and is a well-known component of psoriatic arthritis (PsA). It is part of the stem requirements of the CASPAR (Classification Criteria for Psoriatic Arthritis) criteria. However, little is known about the characteristics of enthesitis in patients with PsA.

The aim of this study was to evaluate the incidence, prevalence, and characteristics of enthesitis in patients with PsA.

Methods:

The study population included patients with PsA who were followed at 6 month interval according to a standard protocol from January 2008 to December 2014. Enthesitis was defined as the presence of at least one painful entheseal site of the 18 entheseal insertion locations of the SPARCC (Spondyloarthritis Research Consortium of Canada) enthesitis index. Descriptive statistics are provided. Incidence calculated per patient-year of follow-up.

Results:

 Of 803 patients who were evaluated during this period 281 had enthesitis on at least one visit, with a prevalence of 35%. 192 patients developed enthesitis during the course of follow-up, with an annual incidence of 0.9%. Among the 281 patients with enthesitis the mean (SD) age at enthesitis diagnosis was 49 years (± 12.7) and PsA duration was 11.4 years (± 11.3). At the time of enthesitis the BMI was 30 (± 6.4), mean number of actively inflamed joints was 9.5 (±11.1) and 52 (19%) patients had dactylitis. The mean psoriasis area severity index (PASI) score was 4 (±5.7) and the mean modified nail psoriasis severity index (mNAPSI) score was 6.1 (± 9.9). 31 (11%) patients had a diagnosis of concomitant osteoarthritis, 33 (12%) diabetes mellitus and 42 (15%) fibromyalgia. 81 (31%) patients had elevated ESR, 115 (41%) patients had elevated CRP and 14% were positive for HLA-B*27. The X-ray evaluation revealed plantar spurs in 143 (53%) patients, Achilles spurs in 99 (37%) and sacroiliitis in 116 (42%). The treatment at diagnosis included NSAIDS in 205 (73%) patients, DMARDS in 154 (55%) and biologics drugs in 95 (34%).

Most of the patients had 1 or 2 (110 and 99 patients, respectively) tender entheseal sites. The 3 most common tender entheseal sites were: Achilles tendons, plantar fascia and, lateral epicondyles (24.2%, 20.8% and 17.2%, respectively).

Conclusion:

Clinical enthesitis is common, occurring in 35% of PsA patients. Usually it appears in only 1 or a few sites simultaneously and the most symptomatic locations are Achilles tendons, plantar fascia and lateral epicondyles.

« Back to 2015 ACR/ARHP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/enthesitis-in-psoriatic-arthritis-incidence-prevalence-and-characteristics/