Original Article
Copyright ©2013 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Diabetes. Aug 15, 2013; 4(4): 135-144
Published online Aug 15, 2013. doi: 10.4239/wjd.v4.i4.135
Association of comorbidities with increasing severity of peripheral neuropathy in diabetes mellitus
Shafina Sachedina, Cory Toth
Shafina Sachedina, School of Medicine, Royal College of Surgeons Ireland, Co. Dublin 2, Ireland
Cory Toth, Department of Clinical Neurosciences, the University of Calgary, Calgary, Alberta T2N 2B1, Canada
Author contributions: Toth C developed the concept and performed all clinical and electrophysiological assessments and verified analyses; Sachedina S grouped the data and performed analysis; both authors contributed to manuscript composition and final editing.
Correspondence to: Cory Toth, MD, Department of Clinical Neurosciences, the University of Calgary, HMRB 155, Foothills Hospital, 3330 Hospital Dr. NW, Calgary, Alberta T2N 2B1, Canada. cory.toth@albertahealthservices.ca
Telephone: +1-403-2208831 Fax: +1-403-2838371
Received: January 2, 2013
Revised: June 4, 2013
Accepted: June 19, 2013
Published online: August 15, 2013
Abstract

AIM: To analyze a large population of patients with diabetes and peripheral neuropathy (PN) to determine other meaningful comorbid etiologies for PN.

METHODS: Peripheral Neuropathy is a common complication of type 1 and 2 diabetes mellitus; however, other potential causes for PN may be co-existing in patients with diabetes. A prospective cohort study was performed to assess patients with diabetes and PN. We compared patients having PN due solely to diabetes with patients possessing co-existing comorbidities, performing clinical (Toronto Clinical Scoring System and the Utah Early Neuropathy Scale), laboratory and electrophysiological assessments in all patients.

RESULTS: Patients with either type 1 or 2 diabetes mellitus and co-existing comorbidities did not have more severe clinical or electrophysiological PN phenotypes overall. However, in patients with type 1 diabetes, presence of a lipid disorder was associated with greater PN severity. In type 2 diabetes patients, both a lipid disorder and cobalamin deficiency were associated with greater PN severity. There was no additive effect upon PN severity with presence of three or more comorbid etiologies.

CONCLUSION: The presence of specific, and not general, comorbidities in patients with type 1 or 2 diabetes corresponds with greater PN severity.

Keywords: Diabetic peripheral neuropathy, Comorbidities, Lipidemia, Cobalamin, Methylmalonic acid

Core tip: The cause of diabetic peripheral neuropathy (DPN) has remained elusive. Comorbid conditions may contribute to the severity of DPN. We studied patients with type 1 or 2 diabetes and concurrent DPN in order to identify potential comorbid conditions associated with greater neuropathic deficit. Concurrent lipidemia was associated with worse DPN in either type 1 or 2 diabetes. A concurrent vitamin B12 deficiency increased severity of DPN in type 2 diabetes. Although our results were potentially confounded by higher HbA1C values in patients with comorbid conditions, vigilance should occur for other causes of PN when diabetes is present.