Subclinical pulmonary involvement in active IBD responds to biological therapy.

Objective Increased mortality from respiratory diseases was observed in epidemiologic studies of patients with ulcerative colitis (UC) as a potentially underestimated extraintestinal manifestation. We therefore investigated the presence of pulmonary manifestations of IBD and the potential effect of TNF-α-inhibitors on pulmonary function tests (PFT) in a prospective, longitudinal study. Design 92 consecutive patients with IBD (49 Crohn´s disease (CD), 43 UC) and 20 healthy controls were recruited. 50 patients with IBD were in remission, 42 had active disease with 22 of these being examined prior and 6 weeks after initiating anti-TNF therapy. Pulmonary function tests (PFT) were evaluated using the Medical Research Council (MRC) dyspnea index and a standardized body plethysmography. IBD activity was assessed using Harvey-Bradshaw index for CD and partial-Mayo-score for UC. Data are presented as mean±SEM. Results Patients with active IBD showed significant reduction of PFT. Forced expiration (Tiffeneau index)-values (FEV1%) were significantly reduced in IBD patients with active disease (78.8±1.1) compared to remission (86.1±0.9; p=0.0002) and to controls (87.3±1.3, p=0.001). Treatment with anti-TNF induced a significant relief in obstruction (p=0.003 for FEV1% in comparison to baseline levels). The level of pulmonary obstruction significantly correlated with clinical inflammation scores (HBI or Mayo). Conclusion Patients with active IBD present with significant obstructive abnormalities in their PFTs. Obstruction is related to inflammatory activity with anti-TNF improving PFTs. Pulmonary obstruction and possibly chronic broncho-pulmonary inflammation is an overlooked problem in active IBD that is probably obscured by intestinal symptoms.