Acute cardiometabolic responses facilitating a state of chronic hyperglycemia and renal impairment: the SABPA study

Abstract

"Background: Augmented α-adrenergic response patterns are associated with vascular risk in Africans. The aims of this study were 1) to assess ethnic differences between glucose and cardiovascular responses during acute laboratory stress, and, 2) to assess if these responses are associated with chronic hyperglycemia (HbA1c ≥ 5.7%) and albumin:creatinine ratio (ACR). Methods: Ambulatory BP was recorded of 81 African and 100 Caucasian men. Beat-to-beat BP was obtained during exposure to the Color Word Conflict (STROOP) and Cold Pressor Tests (CPT). Overnight 8h fasting blood and urine samples were collected for biochemical analyses. Results: Augmented glucose responses were demonstrated by the African men in response to the STROOP (p < 0.001) and CPT test (p = 0.001), opposed to their Caucasian counterparts who displayed attenuated responses. In hyperglycemic African men, an enhanced α-adrenergic profile was demonstrated with decreased stroke volume (P = 0.07) and cardiac output responses (P = 0.05). Augmented systolic blood pressure changes during the CPT predicted ACR in African men (Adj R2 0.31: ß, 0.54 (0.23, 0.85). In hyperglycaemic Caucasian men though metabolic changes, i.e. augmented glucose changes to the STROOP test, predicted ACR (Adj R2 0.19: ß, 0.33 (0.02, 0.64). Conclusion: Proneness for a more α-adrenergic driven cardiovascular response profile was associated with augmented glucose responses in African men when exposed to acute laboratory stress. Pressure overload in Africans opposed to metabolic responses in Caucasians suggest different underlying mechanisms for ACR, a marker of renal impairment when in a state of chronic hyperglycemia."