ACR2013: Highly specific and sensitive for Sjögren's syndrome, ultrasound of the salivary gland can also benefit the accuracy of the new ACR criteria for the disorder.
Salivary gland ultrasonography (SGUS) in Sjgren’s Syndrome is shown to be highly specific and very sensitive. Now researchers say it can also help diagnostic accuracy and improve the performance of the new ACR 2012 Sjgren’s criteria.
An Italian study of 107 consecutive patients with suspected primary Sjgren’s Syndrome (pSS) and controls without sicca symptoms (SS) shows that SGUS scores closely correlate with minor salivary gland biopsy, according to lead author Nicoletta Luciano MD of the University of Pisa.
Of the 50 pSS patients with sicca symptoms ≤5 years (n=5) and 57 non-SS controls (most women, mean ages 47 and 53, respectively), thosensitivitywith pSS show significantly higher SGUS scores vs the controls, according to Luciano’s presentation at the 2013 annual meeting of the American College of Rheumatology.
The SGUS cut-of atf ≥1 shows sensitivity of 66%, specificity of 98%, a positive predictive value (PPV) of 97% and a negative predictive value of 73% for pSS diagnosis, Luciano says.
Additionally, SGUS scores correlate with minor salivary gland biopsy focus scores (MSGB/FS) and unstimulated salivary flow rates measured by sialometry.
SGUS is less sensitive than the salivary test and is “probably not interchangeable to correctly identify patients with primary Sjgren’s,” Luciano remarks. “But from a practical point of view, a biopsy is still needed if SGUS is positive.”
A second study shows that SGUS can improve the diagnostic performance of the 2012 ACR classification criteria, which include only 3 objective tests:
• Anti-SSA/SSB serum antibodies or antinuclear antibody (ANA) titer ≥1:320, and serum rheumatoid factor (RF) positivity;
• An Ocular Staining Score (OSS) ≥3;
• A salivary gland biopsy (SGB) focus score of ≥1.
Study co-author Thierry Marhadour MD of the Universit de Bretagne Occidentale in Brest, France, points out that none of thesensitivity tests explores the function or the morphology of the salivary glands.
The study of SGUS by Marhadour and colleagues in 101 patients in Brittany (94.1% women, mean age 57) who have had symptoms for almost seven years finds that adding SGUS improves both the sensitivity and specificity of the new ACR criteria.
The sensitivity and specificity of the ACR serological items are 60% and 96.4%, respectively. The focus score ≥1 has 82.2% sensitivity and 82.1% specificity, while sensitivity for the OSS ≥3 is 55.6% with a specificity of 58.9%.
A SGUS score ≥2 is considered pathologic. So adding a SGUS score of ≥1 increases the sensitivity of the ACR criteria to 84.4% and its specificity to 89.3%, says Marhadour.
A new criteria set including the 3 ACR items as well as SGUS increases the overall sensitivity to 84.4% and specificity to 89.3% – a notable improvement.
“It is a good diagnostic tool and should be included in future consensual classification criteria for pSS,” concludes Marhadour.