血红蛋白影响血氧饱和度的性别特异性阈值:基于藏族住院患者的非线性回归分析OA

Objective:To investigate the complex association between hemoglobin levels and resting pulse oxygen saturation(SpO2)among surgical inpatients in a high-altitude environment,and to define precise,gender-specific physiological adaptation thresholds for hemoglobin,thereby providing evidence-based reference values for health management strategies in high-altitude populations.Methods:This cross-sectional study enrolled adult inpatients from People's Hospital of Xizang Autonomous Region(alti-tude:3 650 m)between January 2023 and October 2024.To rigorously evaluate the relationship between hemoglobin and resting SpO2,multivariate linear regression analysis was performed.Furthermore,re-stricted cubic spline models and likelihood ratio tests were utilized to explore potential non-linear thre-shold effects.Models were adjusted for potential confounding factors,including age,body mass index,hypertension,diabetes,smoking,alcoholism,and comorbid pulmonary diseases.Results:A total of 3 083 inpatients were enrolled in the final analysis,comprising 1 450 males and 1 633 females.The restricted cubic spline analysis revealed a significant non-linear relationship between hemoglobin levels and SpO2 for the total population(non-linear test,P=0.006),indicating a distinct turning point in the dose-response curve.Two-piecewise linear regression models subsequently identified distinct inflection points for each sex.For female inpatients,the hemoglobin threshold was determined to be 15.482 g/dL;Above this level,SpO2 significantly decreased as hemoglobin increased(β=-0.477,95％CI:-0.760 to-0.193,P=0.001).Similarly,for male inpatients,the threshold was identified at 17.288 g/dL;Exceeding this value resulted in a significant inverse correlation between hemoglobin and SpO2(β=-0.344,95％CI:-0.550 to-0.138,P=0.001).Conclusion:This study establishes specific hemoglobin thresholds for oxygenation status in hospitalized patients at high altitude:15.482 g/dL for females and 17.288 g/dL for males.Beyond these cut-off values,further increases in hemoglobin are associated with a deterioration in SpO2,suggesting a transition from physiological adaptation to maladaptive hemoconcentration.These findings highlight the necessity of sex-stratified hemoglobin monitoring and potential preoperative optimi-zation in high-altitude health management to prevent hypoxia-related complications.