Background Ultrasonography has proved more sensitive than physical examination to detect synovitis in rheumatoid arthritis, so we believe it can be useful to identify subclinical joint involvement in patients with Inflammatory Bowel Disease (IBD).
Objectives To evaluate the presence of synovitis with power Doppler ultrasonography (PDUS) in IBD patients without clinically evident musculoskeletal disease and to investigate its correlation with IBD variables.
Methods Cross-sectional study with prospective recruitment of IBD patients, without clinically overt musculoskeletal signs or symptoms, who attended the Gastroenterology out-patients clinic for follow-up during 2013. Gastroenterological, rheumatological and PDUS evaluation, blind to each other, were performed. Clinical assessment included demographics, comorbidities, IBD characteristics (activity, phenotype, evolution time and clinical subtype), work and sport activities and musculoskeletal clinical examination. PDUS evaluation consisted of the detection of grey scale (GS) synovitis and synovial power Doppler (PD) signal in 44 joints (bilateral sternoclavicular, acromioclavicular, glenohumeral, elbow, carpal, MCP, PIP, knee, ankle and MTP joints) using a LOGIQ7 General Electric machine with a 12-MHz linear array transducer. PDUS variables were scored binary (present/absent) and semiquantitatively. Statistical analysis: continuous variables are expressed as mean ± SD or range and categorical variables as number of cases (%). The associations were evaluated by the Student's t test and Mann-Whitney test for continuous variables and by the χ2 test for categorical ones. Pearson and Spearman correlations of PDUS with clinical and analytical variables were analyzed. The intra-reader agreement for PDUS was estimated in all images obtained. Statistical significance was set at p<0.05 (Stata 10).
Results 23 (56.5% male) IBD patients [9 Crohn's disease (CD) and 14 ulcerative colitis (UC)] have been included so far. Clinical variables: Age 42±12 years, evolution time 9 years (range: 0.1-33), CDAI 28±21, Mayo index 0.4±1, DMARD therapy in 91.3% for 5.5±5.3 years, ESR 12±8.8 mm/h and CRP 0.12±0.14 mg/dl. GS joint effusion and synovial hypertrophy in at least 1 joint were present in 91.3% and 100%, respectively, with poliarticular (≥5 joints) involvement in 47.8% and 74%, respectively, which was mostly of mild or moderate intensity. Mild or moderate PD signal was positive in 47.8% of patients. Joint effusion and synovial hypertrophy were more frequent in MTF, MCF and carpal joints and PD signal in carpal and knee joints. We found no association between PDUS variables and clinical or analytical IBD variables, probably due to the yet small sample size. The intra-reader agreement was high (0.8 intra-class correlation variability).
Conclusions Subclinical joint ultrasound abnormalities are common in patients with IBD, regardless of clinical subtype and even in patients with short evolution time and low intestinal activity. Prospective longitudinal studies are needed to define its predictive value of clinically overt musculoskeletal disease and its association with structural deterioration.
Disclosure of Interest None declared