Chronic Hepatitis B Infection in Children and Its Relation to Pulmonary Function Tests: A Case-control Study

Background: The aim of this study was to evaluate the pulmonary function test (PFT) abnormalities, if any, in children with newly diagnosed chronic hepatitis B (CHB) infection over 3 years. Methods: This is an observational case-control study. One hundred children and adolescents with newly diagnosed CHB were enrolled as the patient group that was further subdivided into 2 groups (50 patients each): inactive carriers (group I) and patients in immunotolerant phase (group II). Only 90 patients completed the study. Fifty healthy children of matched age, sex and height served as a control group, only 45 of them completed the study. PFTs in the form of forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), FEV1/FVC, residual volume, total lung capacity, mid-forced expiratory flow of 25%-75% and diffusing capacity of the lung for carbon monoxide were evaluated in all studied children at the start, yearly and at the end of the study after 3 years. Liver function tests were also evaluated. Results: There was a significant progressive decrease in FEV1, FVC, forced expiratory flow, total lung capacity and diffusing capacity of the lung for carbon monoxide in CHB patient groups compared with their pulmonary functions at the start of the study and with the control group (P < 0.05), while FEV1/FVC and residual volume showed nonsignificant change (P > 0.05). Conclusions: Subclinical PFT abnormalities are present in children with CHB more than we expected. So, PFT monitoring is recommended in pediatric patients with CHB.