Cardiac autonomic neuropathy as risk factor of diabetic complications progression

Abstract

Introduction. Diabetes mellitus (DM) is the most common and incapacitating endocrine disorder. Diabetic foot syndrome (DFS) is one of the most serious complications of DM, which is the main cause of nontraumatic lower-extremity amputations. Despite the efforts of the entire medical community, the survival rate of DFS patients with non-healing ulcers and after foot surgery does not exceed 50% over 5 years and is comparable to the survival rates of patients with colorectal cancer.Aim. It has been demonstrated that postsurgical diabetic foot wounds tend to chronization of inflammatory process. The diabetic autonomic neuropathy can be involved in diabetic foot damages. We hypothesized that progression of cardiovascular autonomic neuropathy  (CAN) leads to aggressive microvascular complications of  diabetes and delay the  postsurgical wound healing in diabetic foot patients during 2 years of observation.Materials and methods. We examined 94 outpatients with postsurgical diabetic foot wounds and observation period of two years. The clinical neurological examination and standard cardiovascular autonomic reflex tests with identification of severe/advanced abnormalities were performed at baseline and after 2 years. The progression of CAN was diagnosed in cases of an increase in the amount of cardiovascular autonomic reflex tests by 1 score and more. The unsatisfactory result of wound treatment was detected in patients with wound healing delay and new cases of surgery debridement, foot amputations and Charcot foot during 2 years of observation.Results. The mean duration of diabetes was 10.7 year, HbA1c 8.3%, LDL-Chol 3.3 mmol/l, TG 1.8 mmol/l. The 51.1% patients had been amputated in the level of foot, 48.9% patients had surgery debridement. All patients had CAN, confirmed/severe forms in 57.4% cases. The progression of CAN was found in 22.3% patients, the most of them with functional stage at baseline. The aggressive course of CAN increased the risk of progression of diabetic sensomotor neuropathy (OR = 14.6; 95% CI 3.0–70.5; p = 0.0006), nephropathy (OR = 22.4; 95% CI 3.4–147.4; p = 0.0009) and unsatisfactory result of wound treatment (OR = 40; 95% CI 6.0–268.5; p = 0.0001).Conclusions. The patients with diabetic foot surgery wounds has high risk of confirmed/severe CAN and its progression during 2 years. The aggressive course of CAN associates with unsatisfactory result of wound treatment and progression of microvascular diabetic complications.