Blood oxygen saturation and its associations with autonomic and peripheral neuropathy in diabetes

Aim. - Individuals with diabetes have lower blood oxygen saturation (SpO 2 ), and hypoxia is suggested to play a role in the pathophysiology of diabetic complications, including diabetic polyneuropathy (DPN). This study investigated whether lower SpO 2 was associated with DPN. Methods . - The study involves participants with type 1 and type 2 diabetes from a cross-sectional study. SpO 2 was measured in the supine position with fingertip pulse oximetry. To assess multiple domains of peripheral and autonomic nerve function, several different standardized tests were used, including autonomic tests, sensory measures, nerve conduction and symptom scores. Odds ratios (OR) were adjusted for relevant covariates and calculated as a function of a 1%-point decrease in SpO 2 for type 1 diabetes and type 2 diabetes, respectively. In addition, ORs were calculated between participants with low (< 96%) and high (≥ 96%) SpO2 levels. Results . - Among 1,515 participants with diabetes, lower blood oxygen saturation (SpO₂) was associated with markers of DPN. In type 1 diabetes (n = 753), each 1%-point lower SpO₂ was associated with higher odds of abnormal sudomotor function in the hands and feet and impaired vibration perception, independent of conventional risk factors. In type 2 diabetes (n = 762), lower SpO₂ was associated with cardiovascular autonomic neuropathy and neuropathic pain. Results were largely similar when SpO₂ was analyzed categorically (< 96% vs ≥ 96%). Conclusion. - Lower blood oxygen saturation was associated with sudomotor dysfunction and impaired vibration perception threshold in type 1 diabetes, and with cardiovascular autonomic neuropathy and neuropathic pain in type 2 diabetes.