Neurological Involvement in Patients with Primary Sjögren's Syndrome: A Retrospective Cross-Sectional Study

To determine the rate and types of neurological involvement in patients with primary Sjögren's syndrome (pSS) and to evaluate predictive clinical and immunologic features of neurological involvement.

We retrospectively assessed 2127 patients with an ICD-10 code for Sjögren recorded in the hospital database. Among these patients, those meeting the pSS classification criteria and having neurological symptoms and an objective evaluation accordingly were enrolled. After comparing the patients with and without neurological involvement, peripheral and central involvement subtypes were also compared within themselves.

A total of 199 pSS patients were enrolled and neurological involvement was found in 31.6%. Peripheral nervous system (PNS) involvement was found in 23.5% of the patients, and central nervous system (CNS) involvement was found in 34.3%. Patients with neurological involvement had a higher frequency of Schirmer's test, anti-Ro/SS-A and anti-La/SS-B positivity and the presence of interstitial lung disease, articular involvement, lymphadenopathy, anemia and hypocomplementemia than patients without those. In multivariate regression analysis, only articular involvement had a higher risk for the development of neurologic involvement [OR 10.01 (4.18-23.97), P 0.0001]. Among the patients with PNS, the frequency of anti-Ro/SS-A positivity, low C3 and Schirmer's test positivity were statistically increased compared to those who were not in PNS (P = 0.032, P = 0.044, and P = 0.029, respectively). When compared in terms of CNS involvement, patients with CNS involvement were younger, had a shorter disease duration, and had a higher frequency of anti-Ro/SS-A positivity than patients without those (P = 0.041, P = 0.027, and P = 0.046, respectively).

In our study, it was shown that one third of the symptomatic pSS patients had objective neurological involvement. The presence of neurological symptoms should be considered, especially in patients with articular involvement in pSS.