Operational characteristics of ultrasound in the diagnosis of Sjögren's syndrome

Abstract

Background and objective: To determine the operational characteristics of salivary gland ultrasound (SGU) in the diagnosis of Sjögren's syndrome (SS) in a population of colombian patients with dry symptoms.

Materials and methods: Study of diagnostic tests in patients with dry symptoms who consecutively attended the rheumatology consultation (2018-2020). Sociodemographic and clinical data were obtained through a survey, paraclinical and ophthalmological tests, minor salivary gland biopsy, unstimulated salivary flow and SGU (score 0-6 based on De Vita) were done. Sensitivity, specificity, positive (PPV) and negative (NPV) predictive values (Stata 15®) were calculated. The receiver operating characteristics (ROC) curve was developed.

Results: 102 patients were included (34 SS and 68 non-SS), mean age 55.69 (±11.93) years, 94% women. Positive ultrasound (score of 2 or more) was more frequent in the SS group, (70.6% vs. 22.1%, P<0.0001). The sensitivity was the same for grade 2 and 3 (70.59%), with a higher specificity (89.71%) for grade 3 (PPV 77.42% NPV 85.92). The ROC curve from the sum of the glands by means of ultrasound was better than those of the independent glands. The ROC curve of the ultrasound presented a greater area under the curve (0.72 [0.61-0.82]) than that of the histological analysis (focus score) (0.68 [0.59-0.78]), P=0.0252.

Conclusion: Salivary gland ultrasound is a useful and reliable method for the classification of SS. Its use could be considered in the future within the SS classification criteria.

Keywords: Diagnostic imaging; Diagnóstico imagenológico; Sensibilidad y especificidad; Sensitivity and specificity; Sjogren's syndrome; Síndrome de Sjögren; Ultrasonografía; Ultrasonography.