Cardiovascular Risk Through Hypoxic Burden in Children With Sleep Apnea

Importance: Emerging biomarkers, such as hypoxic burden (HB), have demonstrated utility in estimation of cardiovascular (CV) risk in adults with obstructive sleep apnea (OSA). Its applicability in pediatric OSA remains unexplored. Objective: To explore whether HB is associated with disturbances in blood pressure (BP) patterns in pediatric OSA. Design, Setting, and Participants: Children with suspected OSA were included in this secondary analysis performed within the framework of the Kids Trial, a prospective, multicenter nonrandomized clinical trial, with data accrued between January 30, 2018, and August 28, 2023, at 2 university hospitals in Spain. A total of 286 children with suspected OSA were assessed for eligibility. Ninety-six children for whom HB was unavailable or with BP data that did not fulfill quality criteria were excluded. Main Outcomes and Measures: Children underwent polysomnography and 24-hour ambulatory BP monitoring (ABPM). HB was quantified as the area under the desaturation curve of each respiratory event, relative to the pre-event baseline oxygen saturation. BP variables were obtained from ABPM. Results: A total of 190 children were included in the analysis. Median age was 6 (IQR, 5-8) years, and 108 participants (56.8%) were male. Median apnea hypopnea index was 6.0 (IQR, 3.1-10.3) events per hour with a median HB of 9.6 (IQR, 3.8-22.5) %min/h. A comparison of the HB quartiles revealed that higher HB levels were associated with greater nocturnal diastolic BP (quartile 1: 56.0 [IQR, 52.0-60.0] mm Hg; quartile 2: 57.0 [IQR, 54.0-61.0] mm Hg; quartile 3: 59.0 [IQR, 53.0-61.0] mm Hg; and quartile 4: 58.0 [IQR, 55.0-61.0] mm Hg; P = .03), a reduced nocturnal decrease in mean BP (quartile 1: 13.5 [IQR, 8.0-18.2] mm Hg; quartile 2: 10.8 [IQR, 8.3-15.1] mm Hg; quartile 3: 11.4 [IQR, 8.7-15.2] mm Hg; and quartile 4: 8.9 [IQR, 6.6-13.5] mm Hg; P = .01), and an increased prevalence of a nondipping pattern (NDP) (quartile 1: 15 of 47 [31.9%]; quartile 2: 21 of 47 [44.7%]; quartile 3: 19 of 46 [41.3%]; and quartile 4: 26 of 47 [55.3%]; P = .04). Multivariable analysis showed an increased risk of NDP in the higher quartile of HB (odds ratio, 2.41; 95% CI, 1.00-5.79; P = .05). Conclusions and Relevance: In this secondary analysis of a nonrandomized clinical trial, elevated HB values were associated with an NDP and reduced nocturnal decrease in BP in children with OSA, both of which are established markers of CV risk. These results suggest the potential utility of HB as a biomarker for CV risk stratification and clinical management in the pediatric population with OSA.