Association of complete blood count–derived inflammatory indices with obstructive sleep apnea severity in symptomatic preschool children: a retrospective single-center study

Obstructive sleep apnea (OSA) is a common sleep-related breathing disorder in preschool-aged children. Untreated OSA is associated with multisystemic pathophysiological consequences, including cardiovascular, metabolic, neurocognitive, and behavioral impairments, that may adversely affect growth, neurodevelopment, and quality of life. Timely identification is therefore critical for early intervention and improved long-term outcomes. This study sought to investigate the associations between complete blood count (CBC)-derived inflammatory indices and the severity of OSA in symptomatic preschool children. Preschool children aged 3–6 years old who presented with snoring symptoms and underwent laboratory polysomnography (PSG) at our sleep center were included. Venous blood samples were collected in the morning following the completion of PSG for CBC analysis. Seven composite indicators were calculated, including Neutrophil/Lymphocyte Ratio (NLR), Platelet/Lymphocyte Ratio (PLR), Monocyte/Lymphocyte Ratio (MLR), Systemic Inflammation Index (SII), Systemic Inflammatory Response Index (SIRI), Aggregated Index of Systemic Inflammation (AISI), and White Blood Cell/Mean Platelet Volume Ratio (WMR). A total of 238 children were enrolled in this study; 74 (31.1%) were classified as having moderate-to-severe OSA and 164 (68.9%) were assigned to non-moderate-to-severe OSA. Compared with the non-moderate-to-severe OSA group, WBC, WMR, SIRI and AISI were significantly higher in the moderate-to-severe OSA group (p < 0.05). Univariable logistic regression revealed that elevated WBC, AISI and WMR were significantly associated with moderate-to-severe OSA, while age, sex, BMI-z score and the other blood indicators were not statistically significant predictors. Logistic Regression analysis fitted by Penalized Maximum Likelihood indicated that WMR was a significant risk factor for moderate-to-severe OSA (OR: 9.006, 95% CI: 2.733–33.759; P < 0.001). Receiver operating characteristic (ROC) analysis showed that the area under the ROC curve (AUC) for WMR was 0.629 (95% CI: 0.553, 0.704; P < 0.001). At the optimal cutoff value of 0.806, the sensitivity and specificity were 74.3% and 47.6%, respectively. CBC-derived inflammatory indices—WBC, AISI and WMR, were significantly associated with moderate-to-severe OSA in symptomatic preschool children. WMR remained independently associated with moderate-to-severe OSA after adjustment. However, its discriminatory capacity was suboptimal—warranting further validation in prospective multicenter studies. Not applicable.