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Differences in respiratory arousal threshold in C aucasian and C hinese patients with obstructive sleep apnoea

2017; Wiley; Volume: 22; Issue: 5 Linguagem: Inglês

10.1111/resp.13022

1440-1843

Richard W. W. Lee, Kate Sutherland, Scott A. Sands, Bradley A. Edwards, Tat On Chan, Susanna S. Ng, David S.C. Hui, Peter A. Cistulli,

Cardiovascular and Diving-Related Complications

ABSTRACT Background and objective Ethnic differences in obstructive sleep apnoea ( OSA ) phenotype may not be limited to obesity and craniofacial factors. The aims of the study were to (i) compare the proportion of Caucasians and Chinese patients with a low respiratory arousal threshold ( ArTH ) and (ii) explore the influence of anatomical compromise on ArTH . Methods Interethnic comparison was conducted between cohorts of Caucasian and Chinese patients from specialist sleep disorder clinics. Polysomnography and craniofacial photography were performed. A low respiratory ArTH was determined by an ArTH score of 2 or above (one point for each: apnoea–hypopnoea index ( AHI ) < 30/h, nadir oxygen saturation ( SaO 2 ) > 82.5%, fractions of hypopnoeas > 58.3%). Anatomical compromise was stratified according to the photographic face width measurement. Results A total of 348 subjects (163 Caucasians and 185 Chinese) were analysed. There was a significantly lower proportion of Chinese patients with moderate‐severe OSA ( AHI ≥ 15) who had a low ArTH (28.4% vs 48.8%, P = 0.004). This difference remained significant among those with severe OSA ( AHI ≥ 30) (2.6% vs 17.1%, P = 0.02). The proportion of moderate‐severe OSA Caucasians with a low ArTH was significantly less in those with severe anatomical compromise (36.6% vs 61.0%, P = 0.03), whereas there was no difference in Chinese patients (25.5% vs 31.5%, P = 0.49). Conclusion Compared to Caucasians with severe OSA , a low respiratory ArTh appears to be a less common pathophysiological mechanism in Chinese patients. Caucasians with less severe anatomical compromise exhibit evidence of a lower ArTh , an association which is absent in Chinese patients. Our data suggest that OSA mechanisms may vary across racial groups.