Limitations and strengths
There are several limitations in the present study. First, the
diagnostic performance of serum periostin in identifying children with
severe asthma were relatively low. It seems that further studies
including more children particularly with severe asthma can help to
determine different cut-off values with better statistical performances.
Furthermore, periostin is a bone-derived extracellular matrix protein
that is secreted by osteoblasts and in growing children the indicative
role of periostin related to the airway inflammation and consequently
asthma severity may be affected due to the fast-linear growth in
school-age children. On the other hand, it was performed in a center
which was specialized for children with asthma and allergic diseases.
The diagnostic procedures and the longitudinal follow-up of the patients
were made by pediatric allergy and asthma specialists conforming with
the international standard GINA guidelines. Its controlled design with
the inclusion of patients with different severity grades who were under
regular follow-up enabled us to demonstrate the possible interactions
between features related to childhood asthma and periostin.