Abstract Background Childhood obesity is associated with multiple comorbidities, including respiratory impairment. One understudied mechanism is airway dysanapsis—disproportionate growth between lung parenchyma and airway caliber—often reflected by a reduced FEV1/FVC ratio despite preserved FEV1 and FVC. Although the Dysanapsis Ratio (DR) can quantify this phenomenon, its clinical use remains limited due to complex calculation methods and unclear thresholds. Rationale To evaluate a simplified DR formula and establish a clinically applicable threshold to identify dysanapsis in children with obesity, while assessing its relationship with obesity severity and cardiometabolic and respiratory comorbidities. Methods A retrospective review of 110 children aged 6-18 years with BMI 95th percentile and acceptable pulmonary function tests (PFTs) was conducted. DR was calculated using both standard and simplified formulas. Two diagnostic criteria for dysanapsis based on FEV1/FVC thresholds (0.80 and 0.85) were compared. Comorbidities including asthma, obstructive sleep apnea (OSA), small airway obstruction, and metabolic disorders were analyzed across obesity classes. Results The simplified DR formula demonstrated comparable utility to the standard method. A DR threshold of 0.75 effectively identified dysanapsis when combined with an FEV1/FVC ratio 0.80. DR values declined with increasing obesity class and were consistently lower in the presence of respiratory and metabolic comorbidities, especially in Class 2 and Class 3 obesity. Small airway obstruction was associated with the lowest DR values, suggesting possible progression from dysanapsis to pathological airflow limitation. Conclusion A simplified DR formula and threshold of 0.75 offer a practical approach to identifying dysanapsis in clinical settings. Lower DR values are associated with both respiratory and metabolic comorbidities in obese children, supporting the integration of DR into routine PFT interpretation and early screening strategies in high-risk pediatric populations. This abstract is funded by: Memorial Health Services
Peddisetty et al. (Fri,) studied this question.