Study design and participants
A cross -sectional study was conducted at the Pediatric
Clinic of Amirkabir Hospital in Arak, Iran, from January 2019 to
September 2019. To estimate the sample size, we considered type 1 (α)
and type 2 errors (β) of 0.05 and 0.20 (power=80%), respectively, and
serum MDA level as a key variable. Based on a previous study12, SD (σ1) of control MDA was 0.1 µmol/L, SD (σ2) of
case MDA was 0.07 µmol/L, and the difference in mean (d) of insulin
levels was 0.15 µmol/L. We reached the sample size of 9 participants for
each group. The sample size of our study consisted of 25 children
diagnosed with severe community-acquired pneumonia (sCAP), 25 patients
diagnosed with asthma and sCAP, and 25 healthy children.
Pneumonia was defined as an acute pulmonary infiltrate evident on chest
radiography with symptoms and signs of a lower respiratory tract
infection: fever, cough, and purulent sputum. Pneumonia was confirmed
with physical exams, microbiologic culture data, and Chest x-ray. CAP in
children was defined as a lower respiratory tract infection in a child
who has not resided in a hospital or health care facility in the
preceding 14 days. CAP in children is one of the most common acute
infections that require going to the hospital. Children with sCAP, due
to respiratory distress, are not able to eat, drink, and alert. They
also have undesirable hydration status and oxygenation status13-14.
The asthma of children was confirmed by a physician via the symptoms of
recurrent coughing, wheezing, and chest tightness.
Exclusion criteria included children with severely smoking parents and
severe or multiple systemic diseases.