PURPOSE: It has been well known that the patients with long duration of type2 diabetes mellitus (DM) frequently suffer from autonomic nerve dysfunction. The activity of the autonomic nervous system under the condition of nocturnal intermittent hypoxia may alter the pathophysiology of obstructive sleep apnea (OSA). Our objective was to investigate the characteristics of OSA with and without DM.
METHODS: A retrospective comparative pilot study was performed for the patients who underwent overnight pulse oximetry. DM patients also underwent coefficiencies of variance of the R wave to R wave (RR) interval (CVR-R) on electrocardiogram (ECG). Heart rate response (HRR) was defined as the ratio of 3% oxygen desaturation index to 7 beat increase index of heart rate. (3% ODI/7bpm). Fifty OSA patients were enrolled. Sixteen of them had DM treated with oral diabetes medications. Eleven of them had DM treated with insulin and was defined as advanced DM patients. Two groups divided by discriminant analysis of HRR were evaluated. Group A: OSA with good HRR (n=27, mean HRR=0.88), Group B: OSA with poor HRR (n=23, mean HRR=2.16). Non parametric test was used for statistical analysis.
RESULTS: Advanced DM patients (n=12) were all categorized into Group B. Compared to Group A, Group B showed significant decrease of mean SpO2 (93.2±3.8 %, 91.5±6.6 %, p<0.05) and increase of percentage time of SpO2< 90% (42.2±23.4 %, 57.0±22.8 %, p<0.05) while BMI and 3%ODI showed no significant difference.
CONCLUSIONS: We concluded that HRR difference affect the nocturnal oxygen desaturation in OSA.
CLINICAL IMPLICATIONS: Our results suggest that OSA accompanied by advanced DM may aggravate the nocturnal tissue hypoxia as the pathophysiology of OSA associated with the altered heart rate response to nocturnal intermittent hypoxia.
DISCLOSURE: The following authors have nothing to disclose: Satomi Shiota, Hidenori Takekawa, Tomoaki Shimizu, Hirotaka Watada, Kazuhisa Takahashi
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