Assessment of Occult Pulmonary Involvement in Ulcerative Colitis

Inflamm Intest Dis. 2020 Aug;5(3):144-150. doi: 10.1159/000508772. Epub 2020 Jul 1.

Abstract

Introduction: Nearly 50% of patients with inflammatory bowel disease (IBD) experience at least one extraintestinal manifestation. Bronchopulmonary involvement is rare in IBD. Pulmonary function test (PFT) abnormality in cases of ulcerative colitis (UC) has been reported to be 17-55%. Occult pulmonary disease may be diagnosed using variables of the PFT. Hence, we aim to evaluate the frequency and type of pulmonary dysfunction in patients with UC in remission.

Methods: Eighty-three patients of UC in remission and 48 controls underwent the PFT including forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), Tiffeneau value (FEV1/FVC), and midexpiratory flow (MEF 25-75%) rate with a spirometer. The patients were divided based on the age of onset of UC into A1 (<16 years), A2 (16-40 years), and A3 (>40 years) and based on the extent of disease into E1 (proctitis), E2 (left-sided colitis), and E3 (extensive colitis).

Results: Patients with UC had significantly abnormal PFT compared with controls (51 [61.5%] vss. 8 [16.67%]; p = 0.000). Patients with UC commonly had a restrictive pattern (33 [64.47%]) of PFT followed by small airway disease (11 [21.56%]) and obstructive pattern (7 [13.72%]). Pulmonary involvement in cases of UC was more in E3 followed by E2 and E1. Pulmonary involvement was more in the late age of onset of disease. BMI was positively and significantly correlated with FEV1 and FVC. Hemoglobin had a positive and significant correlation with FEV1 while a negative correlation with FEV1/FVC and MEF 25-75%. All predictors except for age were found to contribute in higher risk (OR > 1) for PFT abnormality.

Conclusion: Patients with UC have chronic pulmonary inflammation leading to different patterns of lung involvement in the form of restrictive, obstructive airway, and small airway disease. Patients with UC commonly have a restrictive pattern of pulmonary involvement. Impairment of the PFT is related to the disease extent and the age of onset of disease. Assessment of the PFT using a spirometer is a noninvasive, simple, cost-effective, and reliable method for early detection of occult pulmonary involvement in patients of UC.

Keywords: Extraintestinal manifestation; Occult pulmonary disease; Pulmonary involvement; Restrictive pattern; Ulcerative colitis.