A new UK study published in the American Journal of Respiratory and Critical Care Medicine reveals that obstructive sleep apnea (OSA) is independently linked to diabetic peripheral neuropathy (DPN) in patients with type 2 diabetes mellitus (T2DM). The researchers note that the severity of the DPN is also associated with the degree of OSA as well as the severity of nocturnal hypoxemia.

Leading author, Abd Tahrani, MD, a clinical lecturer in diabetes and endocrinology at the UK’s University of Birmingham says: “OSA is known to be associated with inflammation and oxidative stress, so we hypothesized that it would be associated with peripheral neuropathy in patients with T2DM. This is the first report to identify an independent association between OSA and DPN in these patients.”

The team evaluated 234 adults with T2DM in an observational cross-sectional study using the Michigan Neuropathy Screening instrument, which involved a single overnight home-based cardio-respiratory sleep study in which the participants were monitored by a portable multi-channel device.

The results demonstrated that OSA was independently linked to DPN. The findings remained unchanged after adjusting for various variables, which included gender, ethnicity, age at diabetes diagnosis, and diabetes duration, as well as obesity and other DPN risk factors. Furthermore, the researchers found that the severity of DPN was substantially related to the severity of OSA and nocturnal hypoxemia. The results did not change after adjusting for factors, such as age, obesity, diabetes duration, gender and estimated glomerular filtration rate. The findings also revealed that OSA was linked to a higher nitrosative and/or oxidative level of stress and restricted microvascular blood flow regulation, both of which could be a potential explanation for the link between OSA and DPN.

Dr. Tahrani remarked: “In patients with T2DM, OSA may aggravate and amplify glucose toxicity, which has significant implications for tissues which are susceptible to the complications of diabetes.”

The team acknowledged that their study was subject to limitations, such as the study’s cross-sectional design, not including an interventional group, as well as providing causal evidence required for additional prospective studies.

Dr. Tahrani concluded:

“Additional prospective and interventional studies are also needed to examine the role of OSA and intermittent hypoxemia in the development and progression of DPN in patients with both early and advanced diabetes, and to assess the potential impact of continuous positive airway pressure (CPAP) treatment on DPN.”

Written By Petra Rattue