FREQUENCY OF EOSINOPHILIA IN CHILDREN WITH ASTHMA: A CROSS-SECTIONAL STUDY AT THE NATIONAL INSTITUTE OF CHILD HEALTH, KARACHI

Abstract

Asthma is a common chronic respiratory disease of children with airway inflammation frequently driven by eosinophils. Millions of children are affected by asthma in Pakistan, yet few data are available regarding eosinophilic phenotypes. This study sought to determine the frequency of peripheral eosinophilia in pediatric asthma in Pakistan and assess its relation to lung function and clinical severity so that visits can be made phenotype-based in the future.

Materials and methods: A cross-sectional study was conducted at the National Institute of Child Health Karachi from June 2023 to May 2024. A total of 195 consecutive sampled children aged 5–15 years with physician-diagnosed asthma (adult GINA definition) were enrolled. Spirometric measurements (FEV₁, FVC, FEV₁/FVC), blood samples for absolute eosinophil count, and clinical data were collected. Eosinophilia was a relative, defined as an absolute eosinophil count >500 cells/μL. SPSS version 26 was used for statistical analysis. Categorical variables were compared by means of chi square tests and continuous data using the ttest or Analysis of Variance (ANOVA). Predictors of eosinophilia were determined by Pearson’s correlation and logistic regression analysis. The p value < 0.05 was considered significant.

Results: There were 58% males and the mean age was 9.4 ±3.1 years. Among 195 children, eosinophilia was seen in 45.1% (88). In children with eosinophilia, mean FEV% predicted (75.4 vs 85.7, p=0.02), FVC% predicted (82.1 vs 88.5, p=0.04) was significantly lower. A kinetic relationship was found between blood eosinophil count and FEV₁% (r = -0.28, p = 0.0002). When adjusted for all variables with p<0.1 in the logistic regression model, it was found that moderate/severe asthma was independently associated with eosinophilia (adjusted OR=1.8, 95% CI=1.0–3.3, p=0.047).

Conclusion: We conclude that nearly half of asthma children in our study have eosinophilia, reduced lung function and more severe asthma. Measurement of routine eosinophil levels may identify children who would be appropriate for giving the intensive anti-inflammatory therapys.