Pulmonary function trajectories in children with symptom-controlled asthma -a 10-year retrospective cohort study in China.

BACKGROUND

Long-term changes in lung function in children with symptom control asthma are rare. To assess the trajectory of pulmonary function in children and analyze the influence factors.

METHODS

The effects of gender, age, Body Mass Index (BMI), Immunoglobulin E (IgE), eosinophil count, Fractional exhaled Nitric Oxide (FeNO), and so on on pulmonary function pattern were analyzed.

RESULTS

Among the 1931 children, three predicted FEV1 trajectory clusters were identified: downward trend followed by an upward trend (34.96%), downward trend but close to average (32.88%) and continuous downward trend (32.16%). Among the three different trajectories, the first, second, and third clusters had 432 (7.22%), 210 (3.96%), and 327 (3.12%) detections were below the cut point, respectively. And they differed according to the level of FeNO, the count of lymphocyte, interval between diagnosis of asthma and first onset and onset age at enrollment. For FEV1/FVC% pred, 1633 /1931(84.57%) children showed a saddle-shaped form: a gradual rise at first, then a large fluctuation, and finally returned to normal. Other 298 (15.43%) children showed a gradual continuous upward trend. Among the 1858 patients completed of MEF25% pred, 377 (20.29%) had a higher MEF25% pred, 419 (22.55%) children had a trajectory that near the average level, and 1062 (57.16%) children had a trajectory below the average and then catch up at last. Multiple logistic analysis showed that BMI, lymphocyte count, FeNO, time interval of delayed diagnosis and onset age were associated with the change of lung function.

CONCLUSION

Some children with symptom controlled asthma showed a continuous decline in lung function. The decrease of lung function was closely related to BMI, lymphocyte count, FeNO, time interval of delayed diagnosis and onset age.