Clinical Features, Comorbidities, and Hospitalization Patterns in Children Diagnosed with Asthma: A 12-Year Single-Center Retrospective Cohort Study

Background: Pediatric asthma is a complex disease characterized by a variable clinical course and influenced by multiple factors. This study aimed to characterize demographic features, ICD-10 diagnostic categories, documented comorbidities, and factors associated with recurrent hospitalization and hospital resource utilization in children followed in a single-center hospital-based cohort over a 12-year period. Methods: This retrospective observational study included 1080 hospitalizations from 791 unique patients during 2014–2025, reported in accordance with STROBE guidelines. The primary analysis was at the patient level; the episode-level analysis was exploratory. Variables included age, sex, area of residence, ICD-10 asthma diagnostic category, documented anemia, obesity, recurrent hospitalization (defined as ≥2 hospitalization episodes during the 2014–2025 observation period), cumulative hospital stay, mean length of stay per episode and number of secondary diagnoses. Pearson’s χ2 test (with Cramér’s V and unadjusted odds ratios [OR]), the Mann–Whitney U test (with signed rank-biserial correlation, r_rb), the Kruskal–Wallis test (with ε2) and Spearman’s correlation coefficient (ρ) with 95% confidence intervals (95% CI) were used with Benjamini–Hochberg control of the false discovery rate at 5%. Results: Median age was 3.0 years [interquartile range 1.6–6.0; 75th percentile 6.0 years, indicating that approximately three-quarters of patients were in the preschool/early childhood age group], 62.3% of patients were male and 64.1% were from urban areas. The most common ICD-10 diagnostic category was unspecified asthma (J45.9; 60.8%), followed by predominantly allergic asthma (J45.0; 22.9%), mixed asthma (J45.8; 12.6%), non-allergic asthma (J45.1; 3.5%), and status asthmaticus (J46; 0.1%). Overall, 44.8% had documented anemia, 4.8% had obesity and 19.6% had 1 or more recurrent hospitalizations. In unadjusted analyses, documented anemia was associated with recurrent hospitalization (31.1% vs. 10.3%; unadjusted OR = 3.93 [95% CI: 2.68–5.75]; Cramér’s V = 0.260 [95% CI: 0.194–0.324]; q FDR < 0.001), lower age (median 2 vs. 4 years; r_rb = −0.357 [95% CI: −0.431 to −0.283]), longer cumulative hospital stay (8 vs. 6 days; r_rb = +0.364), longer mean stay per episode (6 vs. 5 days; r_rb = +0.211), and higher secondary diagnosis count (8 vs. 7; r_rb = +0.446). Age was negatively correlated with mean length of stay per episode (Spearman’s ρ = −0.302 [95% CI: −0.366 to −0.235]; q FDR < 0.001). Conclusions: The hospital course of pediatric asthma in this retrospective cohort was dominated by preschool-aged children, predominant unspecified ICD-10 coding, a high prevalence of documented anemia as an unadjusted clinical marker, and a subgroup with recurrent hospitalizations and increased hospital resource utilization.