Association between hydrogen sulfide and OSA-associated hypertension: a clinical study

Purpose We sought to unravel the role of hydrogen sulfide (H2S) in the development of hypertension in patients with obstructive sleep apnea (OSA). Methods The study sample included 80 patients with OSA and 45 healthy controls. All subjects underwent measurement of blood pressure (BP) and serum H2S level in the morning. Twentynine of the 39 patients with OSA and concomitant hypertension and 23 of the 41 patients with OSA but no concomitant hypertension received continuous positive alveolar pressure (CPAP) therapy for 4 weeks. Twenty-four-hour ambulatory BP and serum H2S were determined before and after CPAP. Respiratory indices including apnea hypopnea index (AHI), lowest oxygen saturation (SaO(2)), and length of time < 90% saturated (T90) were determined by polysomnography. Results Associations between H2S, BP, respiratory indices, and changes with CPAP were analyzed. OSA patients had significantly higher systolic BP (p= 0.003) and diastolic BP (p= 0.009) and lower H2S levels (p= 0.02) compared to healthy controls. H2S negatively correlated with AHI (p= 0.005), T90 (p= 0.009), morning systolic BP (p= 0.02), and morning diastolic BP (p= 0.03). All respiratory indices were significantly improved (p< 0.05) after CPAP in OSA patients with or without hypertension. BP was significantly reduced and H2S significantly increased after CPAP in OSA patients with hypertension (p< 0.05) but not in OSA patients without hypertension (p> 0.05). Conclusion Multivariate linear regression analysis demonstrated that 24h systolic BP and 24h diastolic BP correlated with H2S as well as their changes after CPAP treatment. Reduction in H2S may play a role in the pathogenesis of hypertension in patients with OSA.