What are the effects of diabetic (diabetes mellitus) neuropathy?

From the Guidelines

Diabetic neuropathy is a common complication of diabetes mellitus that affects the peripheral nerves, causing various symptoms and functional impairments, and its management should focus on strict blood glucose control, pain management with medications like pregabalin, gabapentin, duloxetine, or amitriptyline, and regular foot examinations to prevent complications, as recommended by the most recent guidelines 1. The effects of diabetic neuropathy primarily include pain, numbness, tingling, and burning sensations, typically beginning in the feet and hands and potentially spreading upward. Patients may experience decreased sensation, leading to unnoticed injuries and increased risk of foot ulcers and infections. Motor function can be affected, causing muscle weakness, atrophy, and balance problems. Autonomic neuropathy may disrupt various bodily functions including digestive processes (causing diarrhea, constipation, or gastroparesis), cardiovascular regulation (resulting in orthostatic hypotension), urinary function (leading to incontinence or retention), and sexual function (causing erectile dysfunction or vaginal dryness). Some key points to consider in the management of diabetic neuropathy include:

• The importance of early recognition and appropriate management of neuropathy in people with diabetes, as emphasized in recent guidelines 1.
• The need for annual assessment of diabetic peripheral neuropathy using simple clinical tests, such as the 10-g monofilament test, to identify feet at risk for ulceration and amputation 1.
• The use of pharmaceutical interventions, such as pregabalin and duloxetine, which have received regulatory approval for the treatment of neuropathic pain in diabetes, as recommended by recent guidelines 1.
• The consideration of lifestyle modifications, including regular exercise, smoking cessation, limited alcohol consumption, and proper foot care, as essential preventive measures for patients with diabetes to minimize neuropathy development and progression 1.
• The importance of addressing sleep and mood disorders, which are common comorbidities in patients with diabetic neuropathy, as recommended by recent guidelines 1.

From the FDA Drug Label

14.4 Diabetic Peripheral Neuropathic Pain in Adults The efficacy of duloxetine delayed-release capsules for the management of neuropathic pain associated with diabetic peripheral neuropathy in adults was established in 2 randomized, 12-week, double-blind, placebo-controlled, fixed-dose trials in adult patients having diabetic peripheral neuropathic pain (DPNP) for at least 6 months (Study DPNP-1 and Study DPNP-2).

The effects of diabetes mellitus neuropathy can be managed with duloxetine delayed-release capsules, as they have been shown to statistically significantly improve the endpoint mean pain scores from baseline and increase the proportion of patients with at least a 50% reduction in pain scores from baseline in adult patients with diabetic peripheral neuropathic pain 2.

• Key points:
  • Duloxetine delayed-release capsules are effective in managing neuropathic pain associated with diabetic peripheral neuropathy.
  • The efficacy was established in two 12-week trials in adult patients.
  • Treatment with duloxetine delayed-release capsules statistically significantly improved the endpoint mean pain scores from baseline.
• Dosage:
  • 60 mg once daily or 60 mg twice daily were the doses compared with placebo in the trials.
• Patient characteristics:
  • Patients had Type I or II diabetes mellitus with a diagnosis of painful distal symmetrical sensorimotor polyneuropathy for at least 6 months.
  • Patients had a baseline pain score of ≥4 on an 11-point scale ranging from 0 (no pain) to 10 (worst possible pain).

From the Research

Diabetes Mellitus Neuropathy Effects

• Diabetes mellitus neuropathy is a common complication of both type 1 and type 2 diabetes, affecting up to half of patients with diabetes 3.
• The most common form of diabetic neuropathy is distal symmetric polyneuropathy, characterized by a glove and stocking-like presentation of distal sensory or motor function loss 3, 4.
• Diabetic neuropathy can manifest as progressive distal symmetric polyneuropathy, autonomic neuropathy, radiculo-plexopathies, and mononeuropathies, with each type having distinct effects on patients 3, 4.

Symptoms and Complications

• Diabetic neuropathy can cause a range of symptoms, including pain, numbness, muscle weakness, autonomic dysfunction, and foot ulcers, potentially causing significant impairment to the quality of life for those affected 4, 5.
• Autonomic neuropathy, particularly cardiovascular autonomic neuropathy, is associated with increased mortality, while lumbosacral radiculoplexus neuropathy and treatment-induced neuropathy cause substantial morbidity 4.
• The presence of neuropathy in both insulin-deficient (type 1) and insulin-resistant (type 2) diabetes has caused the majority of preclinical and clinical investigations to focus on hyperglycemia as the initiating pathogenic lesion 6.

Diagnosis and Treatment

• There is currently no single established diagnostic gold standard for diabetic neuropathy, and the best paradigm for screening remains uncertain 3.
• Improved glycemic control is the most effective treatment for diabetic neuropathy, particularly in type 1 diabetes, while symptomatic management is available for painful diabetic neuropathy 3, 4.
• Recent evidence-based guidelines have updated the recommended treatment options to manage pain associated with distal symmetric polyneuropathy of diabetes, including the use of duloxetine and pregabalin 4, 7.
• Identifying and appropriately diagnosing the neuropathies of diabetes is key to preventing progression, and management remains focused on diabetes and metabolic risk factor control and pain management 4.