Reduced Baroreflex Sensitivity in High-Normal Blood Pressure and its Association with Plasma Atherogenicity

Abstract Background Baroreflex sensitivity (BRS) is an early marker of autonomic dysfunction and increased cardiovascular risk. Aim To evaluate BRS in patients with obstructive sleep apnea (OSA) and various blood pressure (BP) levels with a focus on high normal BP, and its association with several cardiometabolic markers, including atherogenic index of plasma (AIP), and triglyceride glucose index (TyG). Methods A total of 80 patients, of whom 40 had newly diagnosed OSA, were divided into subgroups based on BP level—normotension (NBP), high normal BP (HNBP), and arterial hypertension (AH). They underwent examination of BRS and metabolic profiling. Statistical analyses were performed to evaluate group differences and associations. Results The median BRS value showed a decreasing trend from NBP to AH. BRS was significantly lower in both HNBP and AH compared to NBP. A similar pattern was observed after evaluating patients without OSA separately. Among OSA patients, a significant difference in BRS was found only between AH and NBP. BRS did not differ significantly between patients with and without OSA. In a model predicting BRS in multivariate linear regression analysis, age, AIP, and arterial hypertension were the only independent significant contributors. Conclusions Our findings indicate significantly reduced BRS in individuals with HNBP, along with association with the marker of plasma atherogenicity (AIP), suggesting autonomic dysfunction before the onset of overt hypertension. Therefore, BRS could contribute to better estimation of cardiovascular risk in selected patients, especially those with HNBP independent of OSA presence. Future research is necessary to explore the underlying mechanisms.