Objectives: The mechanisms responsible for the onset and progression of sensorimotor peripheral neuropathy (SMPN) in type 2 diabetes remain largely unknown. Although a link between hypertension and SMPN has been observed, it is not clear which blood pressure (BP) component (i.e. systolic, SBP; diastolic, DBP; or pulse pressure, PP) is primarily involved. We sought to determine the relationship between BP components and parameters of nerve function in type 2 diabetes.
Design: Cross-sectional study.
Setting: Academic medical centre.
Subjects: A total of 55 consecutive ambulatory patients with type 2 diabetes (age 62.6 +/-8.0 years, mean +/- SD).
Interventions: Measurement of clinic BP and 10 neurophysiological parameters: motor nerve conduction velocity (NCV; median, ulnar, posterior tibial and peroneal nerve), sensory amplitude (AMP) and latency (LAT; median, ulnar and sural nerve).
Results: Univariate analysis showed that age, diabetes duration, SBP and PP were negatively correlated with nerve function. Regression analysis showed that, after correcting for age, duration of diabetes, glycated haemoglobin, body mass index, microalbuminuria and SBP, PP was independently and negatively associated with NCV (median, P =0.011; ulnar, P = 0.001; peroneal, P = 0.006 and posterior tibial, P = 0.005) and signal AMP (ulnar, P = 0.027; sural, P = 0.055), and positively associated with signal LAT (median, P = 0.083; sural, P = 0.021). SBP was negatively associated with signal AMP (median, P = 0.012) and positively associated with LAT (ulnar, P = 0.018). By contrast, DBP failed to show any significant correlation with nerve function.
Conclusions: The PP is strongly associated with neurophysiological parameters of nerve function in patients with type 2 diabetes. This relationship is independent of traditional risk factors and other BP components.