Introduction: We set out to determine the frequency of respiratory symptoms, abnormal lung function, and shrinking lung syndrome (SLS) among patients with systemic lupus erythematosus (SLE) and to determine correlates of SLS.
Methods: Consecutive adult patients who fulfilled the American College of Rheumatology classification criteria for SLE were enrolled. Demographics, clinical, and serologic characteristics were recorded; all patients underwent pulmonary function tests (PFT) and had either a chest X-ray or computed tomography scan. SLS was defined as dyspnea with restrictive lung physiology (defined as a forced vital capacity (FVC) <80% predicted in the absence of obstruction) who did not have any evidence of interstitial lung disease on chest imaging; controls were symptomatic patients with no restrictive physiology and the absence of interstitial changes on chest imaging.
Results: Sixty-nine out of 110 (63%) patients had respiratory symptoms, 73 (66%) patients had abnormal lung function, and 11 (10%) patients met the definition for SLS. In a multivariate model controlling for disease duration, a history of pleuritis, modified American College of Rheumatology total score, seropositivity for dsDNA and RNP antibodies, increased disease duration (odds ratio (OR) = 1.2; 95% confidence interval (CI) of 1.0-1.3, p = 0.04), seropositivity for anti-RNP (OR = 24.4; 95% CI of 1.6-384.0, p = 0.02), and a history of serositis were significantly associated with SLS when compared with symptomatic controls.
Conclusion: Respiratory symptoms, abnormal lung function, and SLS are common in SLE. Clinicians should consider evaluation for SLS among symptomatic patients with long-standing disease and a history of pleuritis.