Patients with primary Sjögren syndrome (pSS) and interstitial lung disease (ILD) often experience prolonged disease course and delayed onset, according to study results published in Clinical Rheumatology.
Investigators conducted a retrospective case control study at Zhejiang Chinese Medical University Affiliated Clinical Hospital to determine the frequency, characteristics, potential causes, and outcomes of ILD among patients with pSS.
Patients with pSS whose high-resolution computed tomography (HRCT) scan was positive for fibrotic features and were hospitalized from August 2013 to August 2022 were included in the analysis. Patients were divided into 2 subgroups according to ILD presence: the pSS-ILD group and the pSS-non-ILD group.
A total of 274 patients with pSS were included in the analysis, with 61 (93.4% women) patients in the pSS-ILD group and 213 (90.1% women) in the pSS-non-ILD group; prevalence of ILD was found to be 22.3%.
Patients in the pSS-ILD group tended to have later onset of pSS (mean age at recruitment, 66.74±10.62 vs 58.49±15.82 years) and longer disease course (6.0 vs 5.0 years), compared with patients in the pSS-non-ILD group, respectively.
The main finding in HRCT scans was a nonspecific interstitial pneumonia pattern, observed among 45.9% of patients.
Factors that increased risk for ILD among patients with pSS included: age greater than 50 years (odds ratio [OR], 4.786; 95% CI, 1.602-14.299; P =.005)], presence of a purpuric rash (OR, 4.695; 95% CI, 1.537-14.339; P =.007), testing positive for antimitochondrial M2 antibodies (OR, 2.582; 95% CI, 1.166-5.722; P =.019), and diabetes diagnosis (OR, 2.514; 95% CI, 1.025-6.167; P =.044).
Prognostic factors for mortality among patients with pSS included advanced age (hazard ratio [HR], 1.240; 95% CI, 1.088-1.413; P =.001)]and history of cancer (HR, 8.411; 95% CI, 1.771-39.934; P =.007).
Diabetes was the second most common complication, affecting 19.7% of patients in the pSS-ILD group and 6.6% of patients in the pSS-non-ILD group (P =.002).
The study was limited by its single-center design, leaving room for potential bias. Additionally, as it was a case-control study, only associations between risk factors and ILD development among patients with pSS could be explored, not causal relationships. Finally, the sample size of men included in the analysis was small and future studies with a broader patient cohort are needed.
The study authors concluded, “Advanced age and cancer history were independent predictors of pSS patient survival, which should be considered during diagnosis and therapy.”
Huang Y, Qiu Y, Xie Z, et al. Risk factors and prognosis of interstitial lung disease for primary Sjögren syndrome patients: a retrospective case‒control study. Clin Rheumatol. Published online July 8, 2023. doi:10.1007/s10067-023-06596-7