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This section provides a brief overview of common diabetes complications along with how to screen, prevent and manage them. More detailed web pages on each complication are in production. 

1. Overview of Diabetes Complications 

Areas of the body that can be affected by diabetes: 

The following complications overview derived in part from Alberta Health Services My Learing Link module: Basic Diabetes Education 10001. Viewers are encouraged to read Diabetes Canada 2018 Clinical Practice Guidelines for detailed chapters specific to each complication. 


Retinopathy (changes or damage to the retina) is the most common diabetes related eye disease. Retinopathy can be a progressive disease and can evolve from the early non-proliferative stage (microaneurysms) to advanced proliferative retinopathy (growth of fragile blood vessels that have the potential to rupture and bleed). Diabetic macular edema is swelling in the area of the retina responsible for 'straight ahead' vision (the macula) and patients can present with blurring or loss of vision. Retinopathy is the leading cause of new cases of legal blindness in people of working age according to Diabetes Canada. There is also an increased incidence of cataracts and glaucoma for persons with diabetes.

Dental Concerns

A person diagnosed with diabetes is at increased risk for dental issues, particularity when their blood glucose is not well controlled. Hyperglycemia increases the risk of developing periodontal disease, which includes bleeding, inflamed gums from bacterial growth and bone resorption (The Essentials 2013).

Vascular Disease 

People living with diabetes are at an increased risk for heart attack (symptomatic and asymptomatic), stroke and peripheral vascular disease. Diabetes is associated with other cardiac risk factors (e.g. hypertension, dyslipidemia, renal dysfunction) and, as a consequence, accelerated cardiovascular age. Diabetes Canada states persons with diabetes generally have a cardiovascular age 10 to 15 years older than their chronological age. Advanced cardiovascular age substantially increases both the proximate and lifetime risk for CVD events, resulting in a reduced life expectancy of approximately 12 years.


Kidney disease is common in patients with diabetes and includes diabetic nephropathy, ischemic damage due to vascular disease and hypertension and other renal diseases not related to diabetes. Approximately half of all adults living with diabetes will develop signs of chronic kidney disease (CKD) at some time in their life. Diabetic nephropathy specifically is defined as a progressive increase in proteinuria in people with longstanding diabetes followed by declining function that eventually can lead to end stage renal disease (ESRD) requiring dialysis or renal transplantation.

We often simplify diabetic nephropathy to patients by stating that high blood sugars damage the filters in our kidneys so that they can no longer filter our blood properly. This causes beneficial proteins to leak into the urine and waste products to build up in the blood. 

Some diabetes educators refer to the analogy of a coffee filter when teaching the concept of nephropathy to clients. For example, high glucose levels and/or high blood pressure levels could act to damage the filters in the kidneys the same as putting a coffee filter under a tap running at full water pressure. The end result would be theoretical “holes” causing items to leak through when the filter is used. The item leaking through would be albumin. This would be one of the first indicators of damage to the kidneys.


Diabetes related neuropathy can affect the peripheral or autonomic nerves, or a focal group of nerves.
Peripheral neuropathy, the more commonly associated neuropathy, can cause pain and/or loss of sensation to the hands or feet. Numbness and tingling are the most common symptoms. Patients who have detectable peripheral neuropathy are at increased risk for the development of foot ulcerations.
Autonomic neuropathy (changes to the non-voluntary, non-sensory nervous system) can cause changes to digestion (gastroparesis), bowel and bladder control, and perspiration. The nerves that support blood pressure regulation can also be affected. In some cases autonomic neuropathy can lead to hypoglycemia unawareness as the fight or flight response is blunted.
Focal neuropathy typically affects a single or specific grouping of nerves, and symptoms will vary depending on the nerve group affected (e.g. carpel tunnel syndrome).
According to Diabetes Canada, nearly half (40-50%) of people diagnosed with diabetes will develop detectable systemic nerve damage within 10 years onset. Although not all patients with neuropathy have motor or sensory symptoms, the neuropathic pain associated with symptomatic disease is frequently bothersome and often limits physical activity, quality of life and work productivity (Diabetes Canada).

Sexual Dysfunction 

Sexual dysfunction is common in individuals with diabetes and caused by microvascular disease, macrovascular disease and neuropathy. Erectile dysfunction affects approximately 34% to 45% of adult men with diabetes. Additionally, medications used to manage other diabetes related conditions can also have adverse side effect on sexual function (e.g. antihypertensives and antidepressants). For more information, review Diabetes Canada's chapter on Sexual Dysfunction.

Skin Concerns 

People with diabetes are prone to developing skin disorders such as bacterial infections, fungal infections, and itching. In some cases, skin problems can be the first sign that a person has diabetes. People with diabetes may experience greater loss of fluid from the body due to high blood glucose levels, which can cause dry skin on the legs, elbows, feet and other areas of the body. If dry skin becomes cracked, microbes can enter these areas and cause infection, thus good skin care is essential. Reduced sensation (peripheral neuropathy) can make it harder for patients to detect early skin problems including cuts and ulcers that predispose to infections. Regular monitoring of the skin is imperative to prevent minor skin ailments from evolving into serious diabetes complications, such as diabetic foot ulcers. Glycemic control and appropriate skin care are important factors in preventing skin-related complications.

Foot Problems

If you are talking with a client about travel, exercise, pain, sleep, or barriers to change then you also need to talk about foot care.People with diabetes are at high risk of developing foot complications due to a number of factors: neuropathy, peripheral arterial disease (PAD) and a decreased immune response (Boulton et al, 2008). When combined with suboptimal glycemic control, these factors increase the risk of developing loss of protective sensation (LOPS), foot deformities, and local areas of ischemia in the lower limb and foot. Minor skin alterations such as blisters or cracks between the toes or heels may be slow to heal. These minor complications often develop into diabetic foot ulcers, which become chronic wounds that are difficult to treat and very costly. Amputations of the lower extremity and foot are most often preceded by a diabetic foot ulcer.

2. Complication Screening, Prevention and Management

3. Complications that Affect Glycemia - Case Review 


Case #1:

Meet Betty, a 45 year old woman who has had type 1 diabetes for 30 years. She tells you that she has been struggling to control her blood sugars, often dropping low 1-2 hours after eating. She has been losing weight due to poor appetite and feels nauseated when she is able to eat. She tells you she often feels like food is sitting 'like a lump' in her stomach. 


What diabetes complication may Betty be experiencing and need further investigation for? 

What strategies can we suggest to help Betty manage her blood sugars with this complication? 

Click here for discussion answers 






Case #2: 

 Ken has had type 2 diabetes for 30 years and is being followed by nephrology for CKD- Chronic Kidney Disease. His GFR is 15. A1c 7.5%. 

Current diabetes medications include Gliclazide (secretagogue) 160 mg twice a day and Sitagliptin  (DPP-4 inhibitor) 25 mg once a day. 

Upon assessing safety factors you find out that Ken is waking in the morning with low blood sugars. He will also have about 4-5  low blood sugars per week during the day. 


What could be the reason(s) for Ken's low blood sugars? 

What kind of treatment strategies might you suggest? 

Click here for discussion answers 

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