Background Enthesitis is a primary clinical feature in Ankylosing spondylitis (AS). It is an inflammatory process that affects the site of insertion of ligaments and tendons into bone. Elevated enthesitis scores were reported to be associated with worse outcomes in patients with AS.

Objectives This study was performed to investigate the relation between enthesitis and disease activity, functional status, fatigue, joint mobility, radiological damage, laboratory parameter and quality of life in patients with AS.

Methods A total of 421 patients with AS (323 men and 98 women) who included in the Turkish League Against Rheumatism Registry were enrolled in the study. The Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), fatigue, the Bath Ankylosing Spondylitis Functional Index (BASFI), the Bath Ankylosing Spondylitis Metrology Index (BASMI), the Maastricht Ankylosing Spondylitis Enthesitis Score (MASES), AS quality of life (ASQoL), the Bath Ankylosing Spondylitis Radiology Index (BASRI) and ESR were evaluated.

Results The mean ages and disease duration were 39.66±10.81years and 12.05±0.70 months, respectively. Enthesitis was present in 27.3% and absent in 72.7% of patients with AS. There was a positive correlation between MASES and BASDAI (p<0.001), MASES and BASFI (p<0.001) and also MASES and fatigue (p<0.01). MASES was negatively correlated with disease duration and body mass index (BMI) (p:0.017 and p:0.047 respectively). MASES was not correlated with age, BASRI, BASMI, ASQoL and ESR (p>0.05). The mean number of MASES was 1.15±2.40. The most frequent regions of enthesopathies were right iliac crest, spinous process of L5, proximal to the insertion of left achilles tendon, left iliac crest, left first costochondral jointrespectively.

Conclusions Enthesitis was found to be associated with higher disease activity, higher functional status and higher fatigue, lower disease duration and lower BMI. However, we could not find any association between enthesitis and joint mobility, radiological damage, quality of lifeand laboratory parameter.

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Disclosure of Interest None Declared