Abstract
Systemic hypertension is associated with obstructive sleep apnoea syndrome (OSAS) but the pathophysiological mechanisms are incompletely understood. A collaborative European network of 24 sleep centres established a European Sleep Apnoea Database to evaluate cardiovascular morbidity associated with OSAS.
11 911 adults referred with suspected OSAS between March 2007 and September 2013 underwent overnight sleep studies, either cardiorespiratory polygraphy or polysomnography. We compared the predictive value of the apnoea–hypopnoea index (AHI) and 4% oxygen desaturation index (ODI) for prevalent hypertension, adjusting for relevant covariates including age, smoking, obesity, dyslipidaemia and diabetes.
Among patients (70% male, mean±sd age 52±12 years), 78% had AHI >5 events·h−1 and 41% systemic hypertension. Both AHI and ODI independently related to prevalent hypertension after adjustment for relevant covariates (p<0.0001 for linear trend across quartiles (Q) of severity for both variables). However, in multiple regression analysis with both ODI and AHI in the model, ODI was, whereas AHI was not, independently associated with prevalent hypertension: odds ratios (95% CI) for Q4 versus Q1 regarding ODI were 2.01 (1.61–2.51) and regarding AHI were 0.92 (0.74–1.15) (p<0.0001 and p=0.3054, respectively).
This cross sectional study suggests that chronic intermittent hypoxia plays an important role in OSAS-related hypertension.
Abstract
These findings indicate that ODI is superior to AHI in the prediction of hypertension in patients with OSAS http://ow.ly/xFn6R
Footnotes
For editorial comments see page 835.
This article has supplementary material available from erj.ersjournals.com
Support statement: The authors also acknowledge the financial support of Philips Respironics PLC and ResMed PLC, which each provided unrestricted grants to support overall maintenance of the European Sleep Apnoea Database (ESADA) Project. These companies had no input into the design or implementation of the ESADA Project and played no role in the design or completion of the present study. Nonfinancial support was provided by the European Sleep Research Society and the European Respiratory Society (ERS) in terms of logistics for communication, meetings and data presentations for the ESADA collaborators. The ERS also funded a Task Force to support the evaluation of associations between obstructive sleep apnoea syndrome and hypertension.
Conflict of interest: Disclosures can be found alongside the online version of this article at erj.ersjournals.com
- Received December 23, 2013.
- Accepted June 4, 2014.
- ©ERS 2014