Diabetic peripheral neuropathy (DPN) is a well known complication of diabetes affecting 50% of all diabetic patients. The symptoms of DPN are sensory but can also affect the motor skills of diabetic patients. We’ve always referred DPN as a peripheral neuropathy affecting the feet and hands. But a 10/2021 research article published in The Journal of Diabetes and its Complications entitled, ‘The cross-sectional association of cognition with diabetic peripheral and autonomic neuropathy – The Grade Study’ might shed some light on how our current thinking regarding DPN might just be wrong. Lets take a closer look at this interesting article.
The authors of this paper studied the cognitive responses of two groups of patients. The first group of patients were type 2 diabetics who have had diabetes for less than 10 years. The second group of patients were not diabetic but suffered from cardiovascular autonomic neuropathy (AN). The researchers assessed cognition in these two groups with standardized tests that measured immediate recall and processing speed. The findings were striking in that group one, the diabetic population showed a measurable decline in these two tests while the second group, the cardiovascular autonomic neuropathy patients, showed no measurable decline in these two cognitive tests.
Knowing that correlation does not constitute causation, we need to proceed carefully with these findings. As a clinician, I’ve always suspected that there was something more to diabetes and DPN than what I had been taught. In chronic disease management, such as diabetes or hypertension you see anecdotal demographic characteristics that you know to be true for each disease. For instance, in patient with hypertension, we all know that many of these patients are anxious. In the diabetes population, we know patients to have a certain disregard for their disease. I’ve heard many diabetic patients tell me that they have witnessed first hand the loss of a limb or blindness due to diabetes in an immediate family member. Yet these diabetic patients are unwilling (or unable) to be good stewards of their own health. Again, this is not every hypertensive or diabetic patient. But ask any primary care doctor about this phenomenon and I’m sure that they’ll agree with this gross representation of their hypertensive of diabetic patients.
My belief is that The Grade Study has identified the fact that we as physicians have misunderstood the complications of diabetes. As a group, why couldn’t physicians see that diabetic nephropathy and diabetic retinopathy were in part to this system neurological change we called ‘peripheral neuropathy’? The importance of this study is that it attempts to redefine neurological complications in diabetes from a local (peripheral) to global (all of the neurological system).
Jerry Groopman, MD is famous for saying that science (medicine) is the accretion of provisional certainties. If we think of our contemporary understanding of diabetic peripheral neuropathy as a ‘provisional certainty’, I think the authors of The Grade Study rocked our world. Thank you to the authors of this paper for thinking out of the box and taking a fresh look at an old problem. Now it’s up to us to do the heavy lifting and gain new insight and improve clinical care.
Jeffrey A. Oster, DPM