Impaired Baroreflex Sensitivity in Patients with Recent-Onset Type 2 Diabetes

Impaired baroreflex sensitivity (BRS) is a sign of diabetic cardiovascular autonomic neuropathy (CAN) which often remains undiscovered during the early course of diabetes. We aimed to determine whether BRS alterations can be detected in patients with recent-onset type 1 and type 2 diabetes. Continuous plethysmographic arterial pressure and R-R intervals were recorded using the Finometer (Finapres Medical Systems) from the left middle finger in 586 participants from the baseline German Diabetes Study (GDS) cohort with type 1 or type 2 diabetes and a known diabetes duration ≤1 year (T1D/T2D [mean±SD]: n=208/378; age: 34.7±11.1/51.6±10.3 years; male: 60/74%; BMI: 24.7±4.2/31.7±6.3 kg/m²; diabetes duration: 6.3±3.3/5.9±3.5 months; HbA1c: 6.5±1.1/6.5±0.9%) and corresponding controls (CON1/CON2: n=74/208; age: 36.4±10.1/49.4±14.8 years; male: 64/64%; BMI: 26.5±4.9/26.6±4.9 kg/m²; HbA1c: 5.2±0.3/5.3±0.3%). BRS parameters included the alpha index of spectral power (BRSα), transfer function cross spectrum (xBRS), and sequence analyses (BRSseq). After adjustment for sex, age, BMI, and smoking, all three BRS measures were reduced in T2D vs. CON2 (BRSα: 10.1±8.6 vs. 15.4±10.2 ms/mmHg; xBRS: 7.84±6.94 vs. 10.4±8.2 ms/mmHg; BRSseq: 9.85±9.07 vs. 13.3±9.6 ms/mmHg) (P≤0.01), while no such differences were observed in T1D vs. CON1. Multiple regression analyses revealed, that systolic blood pressure (SBP) was the strongest determinant of lower BRS in T2D (xBRS/BRSseq/BRSα: β=-0.32/-0.23/-0.22) followed by age (xBRS: β=-0.18) and lower HDL cholesterol (BRSseq: β=-0.23), while in T1D it was age (xBRS/BRSseq/BRSα: β=-0.37/-0.36/-0.34), SBP (xBRS/BRSα: β=-0.26), and BMI (BRSseq: β=-0.24) (all P≤0.01).

In conclusion, reduced baroreflex sensitivity indicates early CAN in recent-onset type 2 diabetes in relation to modifiable risk factors such as higher systolic blood pressure and lower HDL cholesterol.