Our study included 75 patients with diabetes and ischemic heart disease assessed for evidence of cardiovascular autonomic dysfunction, using tests described by Ewing. 26
The study showed that most of our patients had type 2 DM. The mean age affected was found to be 50 years. Most of our patients showed an evidence of cardiovascular autonomic neuropathy (CAN) (94.67%). This is combatable with the results from a large prospective observational study that suggest the incidence of Diabetic cardiovascular autonomic neuropathy is declining in type 1 diabetes, potentially reflecting improvements in the management of risk factors and is also combatable to the study done by Pappachan JM and his colleagues, which showed a significant association between cardiovascular autonomic neuropathy and higher age. 27–28
Worldwide studies showed neither age nor type of diabetes are limiting factors in its emergence; it has been found both in young people with newly diagnosed type 1 diabetes and in older people newly diagnosed with type 2 diabetes. 29–30
The study showed that patients with age group over 50 years had cardiovascular autonomic neuropathy more than other age groups, definitely this can be explained by the fact that with progressing of age and duration of diabetes patients are more prone to develop cardiovascular autonomic neuropathy, this is similar to what was mentioned by researches worldwide. 31–32
The study revealed higher frequency of cardiovascular autonomic neuropathy in patients living in Khartoum, possibly related to easy access to medical services and because the study was conducted in Elshaab teaching hospital so most of the patients were from Khartoum, this is similar to what was reported by Awad M and his colleagues.33
Interestingly, the duration of diabetes was not significantly associated with the development of cardiovascular autonomic neuropathy, this is consistent with the findings of Ellenberg, and to what was mentioned by S.-H. Ko, S.-A. Park and his colleagues. Although diabetes duration has been reported to play an important role in patients with type 1 diabetes, the influence of diabetes duration seems to play a less important role in type 2 diabetes. 34
The majority of our patients with systemic hypertension were found to have cardiovascular autonomic neuropathy, this similar to study conducted in Punjab, and the study done by Awad M. and his colleagues.33
Cardiovascular autonomic neuropathy was observed to occur with high frequency in patients with no smoking or alcohol consumption history. This is in contrast to what was observed in EURODIAB study and this may be attributed to the low use of smoking and alcohol consumption in our culture. 35
Regarding the relation between cardiovascular autonomic neuropathy and cardiopulmonary symptoms, most patients presented with chest pain followed by palpitations, dyspnoea, light headiness and cough. This is in contrast to what was observed In the Detection of Ischemia in Asymptomatic Diabetics (DIAD) study, where the main features of an MI in patients with cardiovascular autonomic neuropathy are: silence, cough, nausea and vomiting, dyspnea, tiredness, and ECG changes. The increase incidence of symptomatology in favor of cardiovascular autonomic neuropathy may due to co existence of other diseases like hypertension, ischemic heart disease and cardiomyopathy. 36
Regarding the incidence of cardiovascular autonomic neuropathy in relation to systemic involvement, higher incidence of cardiovascular autonomic neuropathy was found in patients with symptoms in favor of gastrointestinal involvement. Also it did appear that the prevalence of symptoms in favor of genitourinary system involvement is similar to what was mentioned in the literature and what was mentioned by Awad M. and his colleagues. 33
Cardiovascular autonomic neuropathy was detected in all patients who had fundal changes combatable with retinopathy, indicating higher frequency of diabetic retinopathy, this higher frequency of cardiovascular autonomic neuropathy in patients with retinopathy is consistent with previous studies, which found an association between cardiovascular autonomic neuropathy and microvascular complications (Pittenger GL, and his colleagues). Cardiovascular autonomic neuropathy progression is correlated with diabetic retinopathy, diabetic nephropathy, and an increased urinary microalbumin excretion rate, this finding suggests that clinicians should pay more attention to patients with diabetic retinopathy or nephropathy, over and above the strict glycemic control required for the prevention of cardiovascular autonomic neuropathy. 37
The study showed that most of the patients had no sweating disturbances, but excessive sweating and reduction of sweating was detected in small number of patients. Localized bouts of sweating on the face during eating (gustatory sweating) are reported to be diagnostic of diabetic autonomic neuropathy although they were not seen in this study. 38
Symptoms of feet involvement were detected in a large number of patients (73.33%), most of them had poor glycemic control and they share features of both cardiovascular autonomic neuropathy and peripheral neuropathy, this is in accordance with the other works worldwide. 36–37−38
The high prevalence of cardiovascular autonomic neuropathy among patients with sensory peripheral neuropathy has lead some authors to recommend screening such patients with bedside tests to pick early signs of cardiovascular autonomic neuropathy and then might benefit from improving their glycaemic Control. 38
Cardiovascular autonomic neuropathy was detected in approximately most patients with sympathetic involvement (abnormal response of diastolic blood pressure to sustained hand grip and postural hypotension) and in most patients with parasympathetic involvement (abnormal valsalva, E/I ratio and 30:15 ratio),but with less frequency, this is contrast to what was mentioned in the literature, this may be due to that most our patients had type 2DM, with poor glycaemic control and long duration of undiscovered DM, indicating that presence of autonomic symptoms indicate necessarily a severe form of cardiovascular autonomic neuropathy,this is consistent with Smith's findings. We think that the rigid division of cardiovascular autonomic neuropathy into sympathetic and parasympathetic is not appropriate as both nerves are involved to differing degrees in most patients. Being rarely life threatening (as many doctors believe), the symptoms of cardiovascular autonomic neuropathy received little attention by researchers compared to other diabetic complications. 39–40−41–42−43
It did appear that patients with cardiovascular autonomic neuropathy had significantly higher levels of glycosylated haemoglobin, this in agree with a study done by Pacher P. and his colleagues, this observation is supported by the results found in Ziegler D study, which found that the incidence of autonomic neuropathy was associated with poor glucose control. 44–45