Aims: Few studies have examined how improved metabolic control might influence vibration perception thresholds (VPTs). The aim of this study was to evaluate if improved HbA1c can influence vibration thresholds in adults with type 1 diabetes (T1DM).
Methods: VPTs were investigated at six frequencies (4-125 Hz) using VibroSense Meter in the sole of the foot at two occasions in 159 T1DM patients, at the heads of the first and fifth metatarsal bones, i.e. MTH1 and MTH5, respectively. The participants were divided into three groups: group A: HbA1c improved by more than 1 mmol/mol (n = 95), group B: HbA1c deteriorated by more than 1 mmol/mol (n = 48) and group C: HbA1c unchanged (± 1 mmol/mol) (n = 16) compared to baseline.
Results: In group A, the mean z-score, reflecting the combined effect of all VPTs, improved being lower at the follow-up than at the baseline [0.2 (- 0.3 to 1.2) vs. -0.1 (- 0.7 to 0.8), p = 0.00002]. VPTs improved at 4 and 64 Hz at both MTH1 (metatarsal head 1) and MTH5. The VPTs at 125 Hz frequency improved at MTH5, but not at MTH1. No significant differences were seen in group B or group C.
Conclusions: Lower HbA1c and lower VPTs in T1DM patients were associated with improved VPT, suggesting a reversible effect on nerve function by improved metabolic control.
Keywords: Continuous glucose monitoring; Diabetes; Flash glucose monitoring; HbA1c; Neuropathy; Vibration perception thresholds.