Correlation between severity of obstructive sleep apnea syndrome and red cell distribution width in elderly patients

Abstract

To investigate the correlation between the severity of obstructive sleep apnea syndrome (OSAS) and red cell distribution width (RDW) in elderly patients. A cross-sectional study was conducted among 311 elderly patients diagnosed with OSAS in the snoring clinic between January, 2015 and October, 2016 and 120 healthy controls without OSAS from physical examination populations in the General Hospital of PLA. The subjects were divided into control group with apnea-hypopnea index (AHI) <5 (n=120), mild OSAS group (AHI of 5.0-14.9; n=90), moderate OSAS group (AHI of 15.0-29.9; n=113) and severe OSAS group (AHI ≥ 30; n=108). The clinical characteristics and the results of polysomnography, routine blood tests and biochemical tests of the subjects were collected. Multiple linear regression analysis was used to examine the correlation between OSAS severity and RDW. The levels of RDW and triglyceride were significantly higher in severe OSAS group than in the other groups (P < 0.01). The levels of fasting blood glucose and body mass index were significantly higher in severe and moderate OSAS groups than in mild OSAS group and control group (P < 0.05 or P < 0.01). Multiple linear regression analysis showed that AHI was positively correlated with body mass index (β=0.111, P=0.032) and RDW (β=0.106, P=0.029). The area under ROC curve of RDW for predicting the severity of OSAS was 0.687 (P=0.0001). The RDW increases as OSAS worsens and may serve as a potential marker for evaluating the severity of OSAS.