By Don Rauf
Loud, ongoing snoring may not only be annoying; it also could be a sign of sleep apnea. In diabetes patients, the condition may lead to many health problems, including complete kidney failure.
Some people with diabetes develop a condition called diabetic nephropathy, or kidney damage caused by their diabetes. More protein than usual collects in the urine, and over time, the condition may destroy kidneys to a point where they can no longer function.
Diabetes patients are also more likely to have obstructive sleep apnea, a sleep disorder that causes breathing to stop (for seconds or minutes) or become shallow.
Scientists have recently discovered that patients with type 2 diabetes who have sleep apnea may be more likely to have diabetic nephropathy than diabetes patients without sleep apnea.
For this study, Abd Tahrani, PhD, with the Centre of Endocrinology, Diabetes and Metabolism at the University of Birmingham and Department of Diabetes and Endocrinology at Heart of England National Health Service Foundation Trust in the United Kingdom, and colleagues followed 224 patients with type 2 diabetes.
The prevalence of obstructive sleep apnea was noted in 144 of the patients, and 90 of them had diabetic nephropathy. Patients with sleep apnea tended to be older and overweight. They usually had higher blood pressure and typically had diabetes for a longer duration than others in the study.
Diabetic nephropathy was more often found in patients with sleep apnea than in those without. About 49 percent of individuals with sleep apnea had diabetic nephropathy, compared with 24 percent of those who did not have sleep apnea.
Obstructive sleep apnea increases oxidative stress. As people breathe in oxygen and their cells produce energy, molecules called free radicals are created. The radicals place oxidative stress on cells.
Oxidative stress damages healthy cells, and for diabetes patients with OSA, the higher level of oxidative stress appears to contribute to kidney damage, according to the authors of this study.
Diabetic neuropathy is the leading cause of end-stage renal (kidney) disease. In this investigation, renal function was assessed by eGFR (estimated glomerular filtration rate), which is a measure of how well the kidneys are removing wastes and excess fluid from the blood.
The researchers found that the eGFR declined faster in patients with sleep apnea and type 2 diabetes than in those with type 2 diabetes alone.
“We demonstrated a robust association between obstructive sleep apnea and diabetic nephropathy,” wrote the authors. “This study could form the basis for interventional studies to examine the impact of obstructive sleep apnea treatment on the development and progression of diabetic nephropathy in patients with type 2 diabetes.”
The American Academy of Sleep Medicine (AASM) advises anyone with type 2 diabetes or hypertension to be evaluated for sleep apnea.
This study was published online September 23 in Diabetes Care. This project was funded by the National Institute for Health Research (UK), the UK Novo Nordisk Research Foundation and Sanofi.