Respiratory symptoms are poor predictors of concomitant chronic obstructive pulmonary disease in patients with primary Sjögren’s syndrome

Involvement of the respiratory system, in particular dry airways and chronic obstructive pulmonary disease (COPD), is common in patients with primary Sjögren’s syndrome (pSS). As respiratory symptoms are also common in pSS patients and may have different etiologies, we wanted to evaluate the amount and impact of respiratory symptoms in out-patients with pSS and to assess if such symptoms are related to concomitant COPD. The St George’s Respiratory Questionnaire (SGRQ) was used to assess respiratory symptoms. SGRQ scores were compared between 51 consecutive pSS patients, in an out-patient setting, and 80 population-based controls. The patients were also studied by pulmonary function tests and CT scans of the lungs to assess signs of obstructive airway disease, including COPD, as well as to assess signs of interstitial lung disease (ILD). 41 and 18% of pSS patients were found to have COPD and radiographic signs of ILD, respectively. pSS patients had significantly higher SGRQ scores compared to controls, but no significant differences in SGRQ scores were found between patients with and without COPD. Neither did the small group of pSS patients with ILD significantly differ in SGRQ scores in comparison to patients without ILD. Respiratory symptoms were common in pSS, but were not more common in patients with concomitant COPD. Since pulmonary involvement in pSS is associated with an increased mortality and respiratory symptoms is a poor marker for pulmonary involvement, we suggest that pulmonary function tests should be performed liberally in all pSS patients regardless of symptoms.