Airway obstruction in primary Sjögren's syndrome (PSS)

INTRODUCTION: Airway disease in PSS is reported to be frequent but its severity and clinical relevance remain unclear. We aimed to assess airway obstruction as defined by pulmonary function test (PFT) in patients with PSS. METHOD: Among 502 patients followed in a reference center for PSS, 81 (78 females) non smokers who underwent PFTs from 1990 to 2012 were retrospectively evaluated. Airway obstruction (AO) was defined by either FEV1/FVC <70% of predicted (patent obstruction) or MEF25-75 <50% of predicted (small airway obstruction) or elevated RV/TLC associated with functional residual capacity >120% of predicted (hyperinflation). Clinical and chest CT scan characteristics of patients with airway obstruction were compared with normal PFT patients. RESULTS: Mean age at PSS diagnosis was 53,1 year. Mean disease duration at study was 5.3 year. 73 (90%) patients had respiratory symptoms. 26 patients (32%) had an airway obstruction: 10% a patent obstruction, 15% a small airway obstruction and 7% an isolated hyperinflation whereas 34 patients (42%) had normal PFTs. Clinical impact in AO patients was mild as mean FEV1 was 90% of predicted. Respiratory symptoms had a low positive predictive value for AO (59%). CT scan manifestation in the AO patients was mainly a bronchial thickening. Diffuse sicca syndrome (mostly cutaneous and genital) was significantly more frequent in the AO group vs normal PFT group (61.5% vs 32.4%, p = 0.036). CONCLUSION: Airway obstruction in PSS is frequent, generally mild and is poorly correlated to respiratory symptoms.