Few reports have focused attention on the evolution of airflow obstruction from pre-school ages to adulthood. Non-transplant obliterative bronchiolitis (BO), mostly post-infectious in origin, is a rare obstructive lung disease starting in infancy. Aims: To determine if the pattern of lung function in BO differs from difficult to treat asthma (DTA), to describe that pattern of change, and to examine the effect of clinical covariates on lung function.
Lung function measurements of 30 patients with BO [mean age at first test 9.5 (4.3–21.5)years], from a single center were examined for inclusion. Mixed-model analysis with age as repeated factor was used to retrospectively review lung function in these children in comparison with 28 with DTA [mean age 9.8 (5.9–14.2)years]. Reference values from www.growinglungs.org.uk were used for evaluating spirometry and anthropometric data. Adjustment for age at first diagnosis, admissions to hospital, mechanical ventilation, BMI and time of the year on longitudinal changes in lung function was performed.
Mean Z-scores for FEV1, FEV1/FVC ratio, FVC and FEF25–75 were lower in the BO patients and RV/TLC ratio higher than in DTA patients. Children with BO showed significant lower FEV1 increase (9x) with ageing than DTA patients (adjusted coefficient = 0.023; p = 0.037, CI 95%: 0.001; 0.044). Post-bronchodilator FEV1/FVC ratio in BO patients showed statistically significant decrease with ageing (adjusted coefficient = −0.016; p < 0.001, CI 95%: −0.021; −0.011) when compared to DTA, where, after adjustment, no association between FEV1/FVC and age was found. No association was described between age and the FEF25–75, whereas a significant decrease in RV/TLC ratio was found in both groups of patients with ageing (adjusted coefficient = −0.583; p < 0.001, IC 95%: −0.882; −0.284).
Large heterogeneity in lung volumes growth between BO and DTA, with the most severe compromise seen in BO patients, supports a different pathophysiologic defect. Associated clinical and radiologic patterns are required to find explanations for these findings.
Obliterative bronchiolitis determines a severe impairment of lung function across ages. Milder cases may however, grow undetected and must be actively looked for.
Teresa Bandeira, No Financial Disclosure Information; No Product/Research Disclosure Information