Does ‘Cognitive Neuropathy’ Contribute To Non-Adherence In Patients With Diabetes?

According to the International Diabetes Federation, there are an estimated 371 million people diagnosed with diabetes around the globe.¹ As specialists in lower extremity care, we have a profound appreciation for the lethal role diabetic neuropathy plays in the lives of those we treat.

Diabetic neuropathy can have an impact on motor, sensory and autonomic nerve fibers in this population. We’ve witnessed the misshapen Charcot foot lead to neuropathic ulcers, osteomyelitis and infection resulting in proximal limb amputation, sepsis and even loss of life. Diabetic neuropathy may affect a host of organ systems that set the stage for amyotrophy, nocturnal diarrhea, gastroparesis, gustatory sweating, cachexia, painful peripheral neuropathy, mononeuropathy, cardiac autonomic neuropathy, postural hypotension, neuropathic bladders and impotence.

Less studied is the possible correlation between diabetic neuropathy and cognitive impairment. One could go further and inquire: “Is cognitive neuropathy an unheeded cause of non-adherence?” It is unsettling to think that such a prevalent disease may be another cause of cognitive impairment in the aging community.  

A Closer Look At Factors Affecting Cognitive Impairment

The aging populace faces a multitude of disease states that deleteriously impact cognitive function. These disease states range from Alzheimer’s disease to alcoholism and cerebrovascular disease. On the other hand, we less often consider that diabetes may negatively affect patients’ cognitive ability. The pathway is not clearly understood but the theory is that poor glycemic control leads to oxidative stress, dyslipidemia and inflammation, which impacts the central nervous system.

A study by Moreira and colleagues focused on 94 patients with diabetes (45 of whom had peripheral neuropathy), comparing them with 54 patients without diabetes.² The authors assessed patients’ global cognitive function with the Mini-Mental State Examination, Trail Making Tests A and B and the verbal fluency test. The study authors found that patients with diabetes had significantly lower scores in the Mini-Mental State Examination but noted no differences between patients with diabetes with and without neuropathy for all the cognitive tests. The authors concluded that cognitive function is worse for patients with diabetes but cognitive function does not appear to be related to peripheral neuropathy.

Another proposed mechanism for affecting cognitive ability is the dysregulated release of insulin, resulting in accumulation of amyloid-beta peptide. which follows a similar pathway of Alzheimer’s disease.³ As Kawamura and colleagues note, insulin not only releases amyloid-beta peptide to the exterior of the brain but also promotes an enzyme that degrades amyloid-beta peptide. The authors add that insulin resistance is a mechanism that promotes Alzheimer’s disease.

As diabetes progresses, patient adherence often diminishes, resulting in an accelerated cascade of bleak events. The diabetes pandemic creates grave challenges for the healthcare provider.

A study by Bangen and colleagues indicated an early cognition decline in patients with diabetes.⁴ In addition, studies have directly linked impaired glucose tolerance in patients with diabetes to decreased verbal understanding, lower long-term memory scores and Mini-Mental State Exam results, and multiple forms of dementia in comparison to those without diabetes.^5–8

Can Patient Adherence Contracts Help?

Adherence in the medical sense entails the consistency and accuracy with which someone follows the regimen prescribed by a physician or clinician. While this is a particular challenge in patients with diabetes, perhaps “cognitive neuropathy” may explain why some of our patients are unable to comprehend the instructions we provide them.

I have only been in practice for 11 years but in my young career, I have found patient adherence contracts to be a helpful clinical tool in allowing patients to understand that they are part of the treatment team. Through these simple contracts, patients and I establish a moral obligation to change their behaviors and actions to help me subsequently help them. The contracts have helped patients place responsibility on themselves and I think you will find your patients more inspired to challenge themselves to improve their own health once you put contracts to use. Patients who could benefit from such contracts include those who have struggled with adherence to instructions in the past and those patients who you believe have difficulty with comprehension.  

The contract also serves as a personal certificate that will be helpful when you enlist the support of social workers, health aides, nurses, friends and family members. The key to these adherence contracts is to clearly define the goals that the physician, doctor, and support system can measure such as use of a Charcot restraint orthotic walker, knee scooter, or wheelchair. Other examples include adherence to dressing change instructions, daily foot inspections, and commitment to follow-up appointments.  

The photo at top left shows the foot of a 63-year-old woman with poorly controlled diabetes, a hemoglobin A1c of 10.1 and a body mass index of 50.1. She had sepsis secondary to a gas-producing infection in her plantar left heel four days prior to her presentation. Emergent debridement resulted in a significant deficit to her plantar heel. She achieved wound closure at eight months after her initial presentation and resumed ambulation six weeks after her wound resolved. A patient adherence contract served as a useful clinical tool in the patient’s recovery and return to function. This particular patient previously struggled with adherence to blood sugar testing, follow-up appointments and non-weightbearing instructions. However, the gravity of her severe foot infection initiated a significant change in her behavior.

On her first postoperative day, I formulated a concise, yet specific patient adherence contract to assist her as well as her support system in making positive changes in her behavior. I constructed the document at the bedside in the presence of the patient’s daughter following a candid conversation about the severity of her condition. Enlisting the support of the patient’s daughter was supported with the contract and dramatically improved the patient’s adherence, and played a vital role in her positive outcome.

In Conclusion

Patient adherence contracts are not financial agreements or substitutes for sturdy medical record documentation. These contracts are solely written commitments from your patients about their intent to adhere to the treatment strategy that will improve their health. Optimum control of these factors can go a long way to reduce the risk of progression of diabetic neuropathy.

It is my hope that this article has opened your mind to the concept of “cognitive neuropathy” and encouraged you to use patient adherence contracts to help improve the lives of your patients.

Dr. Canales is Chief of the Division of Podiatry and the Director of the Podiatric Surgical Residency Program at St. Vincent Charity Medical Center in Cleveland.

References
1.     International Working Group on the Diabetic Foot. Available at https://www.idf.org/ .
2.     Moreira RO, Soldera AL, Cury B, et al. Is cognitive impairment associated with the presence and severity of peripheral neuropathy in patients with type 2 diabetes mellitus? Diabetol Metab Synd. 2015; 7:51.
3.     Kawamura T, Umemura T, Hotta N. Curious relationship between cognitive impairment and diabetic retinopathy. J Diabetes Investig. 2015; 6(1):21–23.
4.     Bangen KJ, Gu Y, Gross AL, et al. Relationship between type 2 diabetes mellitus and cognitive change in a multiethnic elderly cohort. J Am Geriatr Soc. 2015; 63(6):1075-83.
5.     Kanaya AM, Barrett-Connor E, Gildengorin G, Yaffe K. Change in cognitive function by glucose tolerance status in older adluts: a 4-year prostpective study of the Rancho Bernardo study cohort. Arch Int Med. 2004; 164(12):1327-1333.
6.     Vanhanen M, Koivisto K, Kuusisto J, et al. Cognitive function in an elderly population with persistent impaired glucose tolerance. Diabetes Care. 1998; 21(3):398-402.
7.     Kuusisto J, Koivisto K, Mykkanen L, et al. Association between features of the insulin resistance syndrome and Alzheimer’s disease independently of apolipoprotein E4 phenotype: cross-sectional population based study. BJM. 1997; 315(7115):1045-1049.
8.     Curb JD, Rodriguez BL, Abbott RD, et al. Longitudinal association of vascular and Alzheimer’s dementias, diabetes, and glucose tolerance. Neurology. 1999; 52(5):971-975.