The prevalence, clinical features, and long-term outcome of patients with primary Sjögren's syndrome with renal involvement

Abstract

This multicenter, retrospective longitudinal study identified primary Sjögren's syndrome (pSS) patients with clinically significant renal involvement, and analyzed factors associated with predisposition. To investigate clinical features and long-term prognosis of renal involvement, we compared the clinical outcomes for the entire cohort based on the presence or absence of renal involvement. Among 1306 pSS patients (mean age, 51 ± 12 years; 98% female), 36 (2.8%) had renal involvement; 17 patients had tubular involvement, 15 had glomerular involvement, one had both, and 3 were unclassified. The presence of anti-La antibodies was associated with renal involvement. Over the median 5-year follow-up period, the renal function did not change significantly; however, 44% of patients with renal involvement showed impaired renal function at the last visit. Impaired renal function at the last visit was inversely associated with baseline renal function and hemoglobin levels. Among the entire cohort, the prevalence of lymphoproliferative disease (LPD) was significantly higher in pSS patients with renal involvement than those without. Renal involvement is a rare manifestation of pSS; however, it is associated with impaired renal function and LPD. Therefore, screening for renal involvement is important for preserving renal function and early detection of LPD.

Keywords: Glomerulonephritis; Kidney diseases; Lymphoproliferative disease; Sjögren’s syndrome.

Fig. 1

Flowchart of patients screening and classification (A) Application of selection criteria and patient disposition. (B) An overview of clinical data collection over time. For each patient with renal involvement, five patients without renal involvement and three patients with persistent alkaline urine (propensity score-matched) were selected.

Fig. 2

The long-term renal outcomes of pSS with renal involvement were grouped into three categories: patients with renal involvement, patients with “persistent alkaline urine” for two consecutive years, without any documented significant renal involvement, and patients without renal involvement. Annual changes in the eGFR according to the groups (A). The proportion of patients with chronic kidney disease (eGFR < 60 ml/min/1.73 m²) among those with renal involvement at baseline visit and the last follow-up. P values from the McNemar test are shown above the bars (B). Proportions of patients with a significant change in renal function (> 20% from baseline) during the observation period (C). In the multivariate logistic regression analysis, adjusted for the observational period and baseline eGFR, renal involvement was identified as an independent predictor for a significant decline in renal function (D).