Lung Function Parameters during Anti-TNFα Therapy in Inflammatory Bowel Disease

Patients with Inflammatory Bowel Disease (IBD) may experience a range of extraintestinal pulmonary manifestations. Anti-TNFα therapy has emerged as a crucial treatment option for IBD patients. Despite the pro-inflammatory role of TNFα in pulmonary diseases, anti-TNFα therapy has no major value in their treatment. Therefore, this study aimed to investigate the prevalence of pulmonary manifestations and the impact of anti-TNFα therapy on lung function parameters in IBD patients.

Thirty two patients with IBD were recruited. These patients received pulmonary function tests prior to and at least 6 weeks after initiating anti-TNFα therapy. Pulmonary function was evaluated by standardized body plethysmography, including the measurement of lung diffusion capacity (DLCO SB).

FEV1 and vital capacity (VC) were within normal range before and during anti-TNFα therapy. Mean residual volume (RV) was moderately increased before initiation of anti-TNFα therapy. RV decreased during the course of therapy, from 2.7 L (interquartile range (IQR) 2.04 - 3.06) or 159% (IQR 129.25 - 184.75) prior to anti-TNFα therapy to 2.5 L (IQR 2.14 - 3.00) or 138% (IQR 127.00 - 165.25) during anti-TNFα therapy (p=0.031 for absolute values and p=0.014 for relative values. DLCO SB was slightly reduced before anti-TNFα therapy and decreased even further during anti-TNFα therapy, from 76.1% to 72%.

Lung function tests in our IBD cohort were almost normal. FEV1 and VC were within normal range. RV was moderately increased, and DLCO SB was slightly decreased. These might indicate an extraintestinal involvement of IBD. During anti-TNFα therapy, RV slightly improved, whereas DLCO SB decreased even further, albeit only slightly. In our IBD cohort, anti-TNFα therapy did not significantly influence lung function parameters.

Our study shows that anti-TNFα therapy in Inflammatory Bowel Disease (IBD) only slightly changes lung function parameters, including diffusion capacity, at least in patients with mild IBD.