Background: Primary Sjogren’s syndrome (pSS) is a chronic, systemic autoimmune disorder characterized by lymphocytic infiltration of exocrine glands including salivary and lacrimal glands, affecting a female-to-male ratio of 9:1. Nephritis is one of the extra-glandular manifestations, occurring in up to 25% of pSS patients. However, previous studies that have determined the prevalence or clinical features of chronic kidney disease (CKD) in pSS patients are very scarce.

Objectives: The purpose of this study is to compare the clinical, immunological, and laboratory characteristics of pSS patients whose renal function has decreased to CKD stage 3 or lower without a clear primary renal disease.

Methods: We conducted a retrospective cohort study for pSS patients who visited Seoul St. Mary’s Hospital between January 2000 and August 2023. Our study only included patients who were consistently followed up for over a year and had their renal function monitored on at least three occasions. We analyzed clinical and laboratory indices, the final renal function, and biopsy findings. Cases in which a clear renal disease, other than pSS, is identified as causing CKD are excluded from the pSS-CKD patients.

Results: Among 2506 patients with incident pSS, 77 patients developed CKD and 9 patients developed ESRD. Median duration from pSS diagnosis to CKD development was 17 months. 1:1 age- and sex-matched propensity score was used to compare the two groups. The majority of patients were female (9:1). The mean age of pSS diagnosis is 60 ± 13 years. Diabetes and hypertension were more prevalent in CKD group compared with non-CKD group, whether the prevalence of dyslipidemia and metabolic syndrome did not differ. Clinical features such as BMI, and blood pressure did not differ between the two groups. The proportions of NSAID use during follow-up between the two groups were similar. SSDAI and ESSDAI score were significantly higher in CKD group compared to non-CKD group. 18 patients had undergone renal biopsy. Tubular interstitial nephritis is most common (5/18).

Conclusion: The majority of pSS patients has remained normal renal function. Impaired renal function and comorbidity such as diabetes and hypertension could be a risk factor for CKD development in pSS patients, suggesting the need for regular renal function monitoring.

REFERENCES: [1] Lin CY et al. Long-term renal prognosis among patients with primary Sjögren’s syndrome and renal involvement: A nationwide matched cohort study. J Autoimmun. 2020 Sep:113:102483.

Acknowledgements: NIL.

Disclosure of Interests: None declared.