Pharmacists Should Educate Diabetic Patients About Cardiac Autonomic Neuropathy Symptoms
Diabetic patients are usually well aware of the risks of peripheral neuropathy, but they don’t always know that they also face a high chance of developing cardiac autonomic neuropathy. Pharmacists should take every opportunity to raise awareness of this type of neuropathy and to remind patients that only tight control of blood glucose can prevent irreparable nerve damage. Counseling about cardiac autonomic neuropathy symptoms gives patients the opportunity to seek an assessment and avoid the risk of cardiovascular events and mortality that comes along with this form of diabetic neuropathy.
Prevalence of Cardiac Autonomic Neuropathy in Diabetic Patients
In the United States, it’s estimated that half of diabetic patients develop some form of neuropathy, which makes it the most prevalent complication.1 Peripheral neuropathy, or distal symmetric polyneuropathy (DSPN), is well known due to foot complications and the fact that it accounts for about 75 percent of all cases of diabetic neuropathy.2 Cardiovascular autonomic neuropathy (CAN) is the second most prevalent form you’ll encounter in diabetic patients.
Obtaining an early diagnosis improves the prognosis for most diseases, but when diabetic CAN is present, it’s imperative to recognize the symptoms as soon as possible. The presence of CAN predicts progression of chronic kidney disease and signals the potential for recurrent cardiovascular disease in patients with type 2 diabetes.3 It’s also a proven independent risk factor for:
- Myocardial dysfunction
- Silent ischemia
- Cardiovascular mortality
- Any major cardiovascular event
- All-cause death
As you might suspect, CAN prevalence depends on diabetes duration. Newly diagnosed patients seldom have autonomic neuropathy, but their chances increase over time:
- Type 1 diabetes – 30 percent prevalence of CAN after 20 years
- Type 2 diabetes – Up to 60 percent prevalence after 15 years
- Youth – 20 percent prevalence in youth with type 1 or type 2 diabetes; more likely in young women and anyone with elevated A1C levels
Here’s the thing to remember: No one should wait 15 years for symptoms to develop. If their blood sugar is hard to control or HbA1c levels vary, then patients should talk to their physician about being screened for CAN. It’s also a good idea to include CAN information when counseling patients with prediabetes or metabolic syndrome, because they’re also at risk.
Educate Patients About Cardiac Autonomic Neuropathy Symptoms
Long before CAN symptoms appear, the first clues for neuropathy come from the patient’s history of blood glucose control. Of course, uncontrolled glucose is the obvious first sign, but it turns out that glycemic variability over time may also predict CAN. A study published in June 2015 reported that variations in blood glucose and HbA1c were independently associated with the presence of CAN in patients with type 2 diabetes.4
Diabetes can lead to damaged autonomic nerve fibers that regulate heart rate, cardiac output, myocardial contractility, cardiac electrophysiology, and blood vessel constriction and dilation.5 As a result, CAN has the ability to cause a range of diseases, from asymptomatic myocardial ischemia and cardiomyopathy to myocardial infarction. Patients may not have any symptoms in the early stages, but they should be advised to consult their doctor if they experience:
- Orthostatic hypotension—most common early symptom of CAN
- Resting tachycardia
- Exercise intolerance
- Abnormal blood pressure regulation
Even when CAN is asymptomatic, it may be detected by decreased heart rate variability while deep breathing. In addition to testing for heart rate variability, cardiac reflex tests and a Holter monitor may be used to obtain a diagnosis.
Treatment Regimens: Glucose control and lifestyle interventions are always first-line treatment. These steps may prevent nerve damage or slow its progression, but it’s interesting to note that intensified glucose and blood pressure management may increase the risk of a cardiovascular event in patients with CAN. In other words, it’s vital for them to consult their physician before making any changes to their regimen.
The following medications may be prescribed to treat orthostatic hypotension or orthostatic tachycardia:6
- Midodrine – A selective alpha1-adrenoreceptor agonist approved for treating orthostatic hypotension.
- Fludrocortisone – Treats orthostatic hypotension by increasing reabsorption of sodium and loss of potassium at renal distal tubules.
- Erythropoietin – May improve orthostatic hypotension but the mechanism isn’t fully understood.
- Nonselective beta-blockers – Medications with intrinsic sympathomimetic activity may improve symptoms, but efficacy in diabetic CAN hasn’t been established.
Pharmacists Should Encourage Diabetic Therapies to Prevent CAN
When you have the opportunity to connect with patients, remember that diabetic neuropathies are often asymptomatic until the damage has progressed, and then the problem can’t be repaired. It helps patients to acknowledge that managing blood glucose is not easy and to let them know you’re there to help. Be sure to offer an information sheet that lists local support groups, diabetes education programs, and exercise programs. Stock your pharmacy with diabetic supplies and beverages, snacks or nutrients developed to support glycemic health. Most importantly, talk with them about the vital role of taking their glucose-controlling medications. Patients with chronic illness like diabetes need all the community support they can get—whether they know it or not, you’re one of their most valuable team members.
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- “Diabetic Neuropathy,” July 2016, http://emedicine.medscape.com/article/1170337-overview ↩
- “Diabetic Neuropathy: A Position Statement by the American Diabetes Association,” January 2017, http://care.diabetesjournals.org/content/40/1/136 ↩
- “Diabetic Cardiovascular Autonomic Neuropathy Predicts Recurrent Cardiovascular Diseases in Patients with Type 2 Diabetes,” October 2016, http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0164807 ↩
- “The Association Between Glycemic Variability and Diabetic Cardiovascular Autonomic Neuropathy in Patients with Type 2 Diabetes,” June 2015, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4462181/ ↩
- “Diabetes and Cardiac Autonomic Neuropathy: Clinical Manifestations, Cardiovascular Consequences, Diagnosis and Treatment,” February 2015, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4317320/ ↩
- “Cardiac Autonomic Neuropathy in Diabetes,” February 2010, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2809298/ ↩