Objectives: To evaluate the diagnostic value of hand ultrasound (US) in systemic sclerosis (SSc) and to explore its relevance within a combined diagnostic approach.
Methods: 224 patients with suspected SSc were consecutively included. They all had US evaluation assessing the presence of fibrotic tenosynovitis (fibrotic TS) and ulnar artery occlusion (UAO). The final diagnosis of SSc was based on the clinical evaluation of a board of experts independently of any pre-established classification criteria.
Results: 166 patients were finally diagnosed as SSc according to the experts as reference standard. 62 SSc and 8 non-SSc patients had UAO (uni or bilateral) (p=0.001). 23 SSc patients and 1 non-SSc patient had US fibrotic TS (p=0.007). A US SSc-pattern (presence of UAO and/or fibrotic TS) was reported in 73 SSc patients and 9 non-SSc patients (p<0.001). UAO had an area under ROC curve (AUC) for the diagnosis of SSc of 0.618 (95%CI 0.539- 0.697); with Se=0.373 (0.304-0.449) and Sp=0.862 (0.751-0.928). Fibrotic TS had an AUC of 0.561 (0.480-0.643); with Se=0.139 (0.094-0.199) and Sp=0.983 (0.909-0.997). The US-SSc pattern had a AUC of 0.641 (0.563- 0.695), with Se=0.440 (0.367-0.516) and Sp=0.845 (0.731-0.916). A scoring system including these US parameters and items from ACR/EULAR classification criteria had an AUC of 0.979 (0.962-0.996)) and allows the substitution of capillaroscopy by US parameters with similar performances.
Conclusions: The use of hand US parameters may help to refine the diagnostic strategy of SSc and their inclusion in a combined diagnostic approach could be discussed.