Background/Purpose: To study the prevalence of chronic obstructive pulmonary disease (COPD) in patients with primary Sjögren’s syndrome (pSS) and its association with respiratory symptoms, pulmonary radiographic findings and clinical features of pSS.

Methods: Fifty-one consecutive pSS patients, diagnosed according to the American-European Classification Criteria (AECC), were recruited from the open clinic at the Dept of Rheumatology, Malmö, Sweden and included in the study. The patients were studied by pulmonary function tests (PFT), CT scan of the lungs, the St George’s Respiratory Questionnaire (SGRQ), The EULAR Sjögren’s syndrome disease activity (ESSDAI) and patient reported indices (ESSPRI) and by laboratory and serological tests. The results were compared with 270 male and 186 female population-based PFT controls standardizing the variables with regard to gender, age, height, weight and tobacco consumption.

Results: pSS patients displayed a significantly decreased vital capacity (VC), forced expiratory volume in 1 second (FEV₁), FEV₁/VC, and diffusion capacity for carbon monoxide whilst the residual volume was significantly increased (Table 1). COPD, according to the GOLD criteria, was diagnosed in 41% of pSS patients (30% in never-smoking and 54% in ever-smoking pSS patients) (Table 2). The SGRQ and ESSDAI total scores were inversely correlated with the VC, TLC and D_LCO. However, radiographic abnormalities, IgG, C3, C4, anti-SS-A and anti-SS-B antibodies, ANA, RF and disease duration were poorly associated with PFT variables.

Conclusion: pSS patients showed signs of both obstructive and restrictive pulmonary disease and 41% fulfilled GOLD criteria for COPD. Respiratory symptoms and disease activity was associated with PFT, whilst radiographic abnormalities, laboratory and serological features of the disease were generally poorly associated with PFT in pSS patients.

Table 1.

Comparison of Pulmonary Function Test (PFT) results in patients with primary Sjögren’s syndrome (pSS). PFT results are presented as % of predicted and in absolute numbers (mean ± SD) and COPD diagnosis in %. In comparisons between measured and predicted PFT values, the paired samples t-test was used.

VC = vital capacity, TLC = total lung capacity, RV = residual volume, FEV₁ = forced expiratory volume in one second, FEV₁/VC = ratio of FEV₁ to VC, D_LCO = diffusing capacity for carbon monoxide, COPD=Chronic Obstructive Pulmonary Disease.

Table 2.

Prevalence of chronic obstructive pulmonary disease (COPD) in ever-smoking and never-smoking patients with primary Sjögren’s syndrome (pSS).