Relationship between obstructive sleep apnoea syndrome and essential hypertension: a dose–response meta-analysis

The objective of this study was to summarize the evidence regarding the relationship between obstructive sleep apnoea syndrome (OSAS) and the risk of essential hypertension. The study was a dose–response meta-analysis of observational studies. The PubMed, Embase, CNKI, VIP and CBM databases were searched to collect relative studies examining the relationship between OSAS and the risk of essential hypertension. Studies were retrieved from database establishment through September 2016, and new literature published between September 2016 and May 2017 was later supplemented. Linear and non-linear dose–response models were used to assess the relationship between apnoea–hypopnea index (AHI), which was used to reflect the severity of OSAS, and the risk of essential hypertension. Stata 13.0 was used for the meta-analysis. Six prospective cohort studies and one case–control study were included, for a total sample size of 6098. The dose–response meta-analysis showed that a high AHI significantly increased the risk of essential hypertension compared with a low AHI (odds ratio (OR) = 1.77, 95% confidence interval (CI) (1.30, 2.41), p = 0.001). The linear dose–response meta-analysis showed that the risk of essential hypertension increased by 17% for every 10 events/h increase in the AHI (OR = 1.17, 95% CI (1.07, 1.27), p = 0.001), and the results of the non-linear dose–response meta-analysis showed that the risk of essential hypertension increased with increasing AHI value. A potential dose–response relationship exists between the severity of OSAS and the risk of essential hypertension. This relationship should be considered when developing prevention measures for essential hypertension.