Changing Patterns of Diagnostic Testing in Children With Asthma: Evidence of Redistribution, Overuse, and Recovery After the COVID-19 Pandemic

BACKGROUND: Real-world implementation of diagnostic strategies in pediatric asthma remains heterogeneous, and the long-term impact of the COVID-19 pandemic on diagnostic practice patterns is incompletely understood, particularly in middle-income countries. Guideline-recommended objective testing (e.g., spirometry) is inconsistently applied in pediatric asthma worldwide, and whether the COVID-19 pandemic produced a transient disruption or a lasting restructuring of diagnostic practice across testing domains remains unclear. We aimed to characterize longitudinal trends in diagnostic testing among children with asthma, examining pre-pandemic trajectories, COVID-associated changes, and post-pandemic recovery. METHODS: We conducted a nationwide population-based interrupted time-series study using Colombia's mandatory healthcare registry (2015-2024). Asthma encounters were identified using ICD-10 codes (J45-J46). Diagnostic procedures were classified into nine clinically defined domains. Diagnostic intensity was calculated as tests per 100 asthma encounters. Segmented regression estimated pre-pandemic trends, immediate 2020 level changes, and post-pandemic slope modifications. RESULTS: A total of 1,954,680 asthma encounters generated 117,324 diagnostic tests. Pre-pandemic trajectories diverged across domains. Pulmonary function testing (PFT) declined before 2020 (IRR 0.80; 95% CI 0.74-0.86) but showed a significant immediate increase in 2020 (IRR 1.42; 95% CI 1.28-1.57) and sustained post-pandemic acceleration (IRR 1.17; 95% CI 1.09-1.26). Imaging and sleep studies exhibited sharp pandemic-associated declines with partial or full recovery. Cardiopulmonary testing demonstrated marked pre-pandemic expansion (IRR 1.96). CONCLUSIONS: Pediatric asthma diagnostic practice underwent domain-specific restructuring rather than uniform disruption, consistent with a process of diagnostic redistribution across testing domains. Post-pandemic intensification of PFT may reflect improved adherence to objective diagnostic confirmation, whereas persistent contraction in selected domains warrants continued monitoring.