Prevalence Patterns of Children's Interstitial and Diffuse Lung Disease (chILD) in Colombia, 2016-2024.

BACKGROUND: Children's interstitial and diffuse lung disease (chILD) comprise a heterogeneous group of rare disorders associated with substantial morbidity and mortality. Population-based epidemiological data remain scarce in low- and middle-income countries, limiting health system planning and policy development. We aimed to estimate the prevalence and temporal trends of chILD in Colombia using nationwide administrative healthcare data. METHODS: We conducted a retrospective, population-based study using Colombia's Registro Individual de Prestación de Servicios de Salud (RIPS) from 2016 to 2024. chILD cases were identified using ICD-10 codes for chILD in individuals aged 0-18 years. Prevalence was estimated overall, by year, sex, age group, and diagnosis. Crude and WHO age-standardized prevalence rates were calculated per 100,000 population. Temporal trends were assessed using Poisson regression and LOESS smoothing. RESULTS: A total of 4608 chILD -related healthcare encounters were identified. The average annual crude prevalence was 3.32 per 100,000 children (age-standardized: 3.39 per 100,000). Prevalence was highest in infants younger than 1 year and showed a secondary increase during adolescence. No relevant sex differences were observed. A significant annual increase in reported cases was detected (IRR 1.022; 95% CI 1.011-1.034), with a marked decline during the COVID-19 pandemic. Alveolar and fibrotic interstitial lung disease categories accounted for most cases. CONCLUSIONS: This first nationwide study provides robust real-world evidence on the epidemiology of chILD in Colombia, revealing substantial healthcare utilization and distinct age-related patterns. Administrative data represents a valuable complementary tool for surveillance of rare pediatric lung diseases.