Monocyte-to-HDL cholesterol ratio in a clinically defined pediatric sleep-related breathing disorder phenotype characterized by witnessed apnea.

OBJECTIVE: The monocyte-to-high-density lipoprotein cholesterol ratio (MHR) is a composite marker of inflammatory-metabolic balance. This study evaluated MHR in children with a clinically defined sleep-related breathing disorder (SRBD) phenotype characterized by witnessed apnea or respiratory pauses. MATERIALS AND METHODS: This retrospective case-control study included 74 children with clinically defined SRBD and 70 controls. Because polysomnography (PSG) was not systematically available, the study group was not classified as PSG-confirmed obstructive sleep apnea. Group comparisons used Holm correction. Age- and sex-adjusted logistic regression and ROC analyses were performed. MHR-, monocyte-, and HDL-based models were compared using DeLong tests, and the MHR model underwent bootstrap internal validation. RESULTS: MHR was higher in the study group [13.84 (11.57-16.48) vs 10.15 (8.78-12.07); Holm-adjusted p < 0.001] and remained associated with group membership after age and sex adjustment (adjusted OR = 1.315, 95% CI: 1.173-1.474; p < 0.001). Adding MHR increased the AUC from 0.563 to 0.777 (DeLong p < 0.001); the optimism-corrected AUC was 0.762. MHR had the highest AUC among single-marker models, but differences versus monocyte- and HDL-based models were not significant after Holm correction. CONCLUSION: MHR was elevated in this pediatric SRBD phenotype and added information beyond age and sex. Its potential value may lie in integrating inflammatory and metabolic information into one readily calculated index rather than in superiority over its components. MHR should be regarded as a complementary research biomarker, not a diagnostic test.