Objective: To test the diagnostic accuracy of modified American-European classification criteria (AEC) for primary SS (pSS) by replacing sialoscintigraphy (sSC) with ultrasonography of the major salivary glands.
Methods: One hundred and ninety subjects were evaluated for the diagnosis of pSS, including US of the salivary glands. We tested the diagnostic accuracy of the three different sets of five diagnostic criteria for pSS. Each set combined these four criteria (ocular symptoms, oral symptoms, Schirmer-I test and auto-SS-A antibody) and one of the following: US (US set), sSC (sSC set) or biopsy (Biopsy set). The area under the receiver operating characteristics curve (AUC-ROC) was used to evaluate the diagnostic accuracy of each set of criteria.
Results: Out of 190 subjects examined, 140 subjects fulfilled the AEC for the diagnosis of pSS, whereas 50 subjects were classified as non-pSS subjects. US score was positive in 129 (92%), sSC in 123 (88%) and biopsy in 93 (66%) of 140 pSS patients. Among 140 patients with pSS, 88 (63%) patients fulfilled the criteria of the US set, 85 (61%) patients of the sSC set and 71 (51%) patients of the Biopsy set. None of the subjects from the non-pSS group fulfilled any of the sets of criteria. Diagnostic accuracy of each of the three sets of criteria was high and similar [AUC-ROC (s.e.) for the US set was 0.99 (0.00), followed by the sSC set at 0.98 (0.00) and the Biopsy set at 0.97 (0.00)].
Conclusion: US finding of major salivary gland involvement could replace sSC in AEC for the diagnosis of pSS.