The association between pulmonary function impairment and colon inflammation in ulcerative colitis patients: A scientific basis for exterior-interior correlation between lung and large intestine.

Objective: To investigated the involvement of pulmonary function impairment in ulcerative colitis (UC), to explore a scientific basis for the Chinese medicine (CM) theory of exterior-interior correlation between Lung (Fei) and Large intestine (Dachang).

Methods: Totally 120 patients with a diagnosis of UC were recruited and the demographics, clinical data, and blood samples were collected. C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) concentrations were measured. Every patient accepted pulmonary function test and took chest radiograph (CXR).> RESULTS: Pulmonary function abnormalities were present in 72 of 120 patients. The median (interquartile range) vital capacity (VC), forced vital capacity (FVC), forced expiratory volume in 1 s (FEV), carbon monoxide diffusion capacity (DL) of lung, total lung capacity (TLC) and functional residual volume (FRV) were decreased in distal UC and pancolitis compared with ulcerative prochitis (P <0.0005). Male patients had increased VC, FEV/FVC, and residual volume (RV)/TLC compared with female (P <0.0005), but decreased DL and carbon monoxide iffusion capacity (K) of lung/alveolar ventilation (P <0.0005). Age was strongly correlated with RV (Spearman rank correlation coefficient (rs)=-0.57,P <0.0001), and RV/TLC (rs=0.48,P<0.0001). Age was also correlated with FEV/FVC (rs=-0.29, P=0.001), forced expiratory flow in 75% vital capacity (FEF75%, rs=-0.20, P=0.03), DL (rs=-0.21, P=0.02), TLC (rs=-0.25, P=0.006), and FRV (rs=-0.28, P=0.002). The course of disease was correlated with FEF75% (rs=-0.18, P=0.049) and K (rs=-0.19, P=0.036). Chest radiograph abnormalities were presented in 38 of 120. Pulmonary symptoms were presented in 10 of 120. Other extraintestinal complications were presented in 21 of 120.

Conclusions: Pulmonary function impairment was more frequently than other extraintestinal complications in UC patients, which may be affected by sex, age, extent and course of disease. These results may be a scientific basis for the theory of exterior-interior correlation between Lung and Large intestine.