Hospitalizations for infections in primary Sjögren's syndrome patients: a nationwide incidence study

Background: Primary Sjögren's syndrome (pSS) is an autoimmune disease with increased risk of infections. Here, we assessed whether pSS patients were at higher risk of hospitalization for community and opportunistic infections.

Methods: We selected newly hospitalized pSS patients between 2011 and 2018, through a nationwide population-based retrospective study using the French Health insurance database. We compared the incidence of hospitalization for several types of infections (according to International Classification for Disease codes, ICD-10) between pSS patients and an age- and sex-matched (1:10) hospitalized control group. We calculated adjusted Hazard Ratios (aHR, 95% CI) adjusted on socio-economic status, past cardiovascular or lung diseases and blood malignancies factors.

Results: We compared 25 661 pSS patients with 252 543 matched patients. The incidence of hospitalizations for a first community infection was increased in pSS patients [aHR of 1.29 (1.22-1.31), p < .001]. The incidence of hospitalization for bronchopulmonary infections was increased in pSS patients [aHR of 1.50 (1.34-1.69), p < .001, for pneumonia]. Hospitalizations for pyelonephritis and intestinal infections were increased [aHR of 1.55 (1.29-1.87), p < .001 and 1.18 (1.08-1.29), p < .001, respectively]. Among opportunistic infections, only zoster, and mycobacteria infections (tuberculosis and non-tuberculous) were at increased risk of hospitalization [aHR of 3.32 (1.78-6.18), p < .001; 4.35 (1.41-13.5), p = .011 and 2.54 (1.27-5.06), p = .008, respectively].

Conclusions: pSS patients are at higher risk of hospitalization for infections. The increased risk of hospitalization for mycobacterial infections illustrates the potential bilateral relationship between the two conditions. Vaccination against respiratory pathogens and herpes zoster virus may help prevent some hospitalizations in pSS patients.KEY MESSAGESPrimary Sjögren's syndrome (pSS) increases hospitalization risk for community infections: bronchopulmonary, skin, dental, ear-nose-throat, intestinal infections and pyelonephritis.Hospitalizations for zoster and mycobacterial infections are also increased in this population.Dedicated preventive measures and vaccination campaigns could decrease the burden of infections in pSS patients.