Leslie Goldenberg, BSc, MD, FRCPC
Internal, Geriatric and Podologic Medicine
Assistant Professor of Medicine, University of Toronto
Medical Director, The Walking Mobility Clinics 

The first principle in the care of the diabetic foot is to recognize the primacy of prophylactic care. Indeed, an ounce of prevention is worth the proverbial pound of cure, even in the patient who appears to be low risk and does not suffer from peripheral neuropathy or vasculopathy. Physicians and other health care professionals have a critically important role to play when it comes to educating their diabetic patients regarding daily foot care, with particular attention paid to the care of skin, nail and callus, proper footwear and strategies to prevent foot trauma and infection. Diabetes remains the most common cause of non-traumatic limb loss, and there is considerable suffering and economic impact associated with the management of chronic diabetic foot pain and sepsis. Two-thirds of diabetic amputations follow complications that are related to foot ulcers.

Pressure platform studies demonstrate that the patient placing a diminished load on the toes is an early finding in diabetic neuropathy. This reduction in the load on the toes leads to a corresponding increase in metatarsal head loads. In addition, there is a shift of loading on the forefoot, away from the medial side, with increasing load now borne under the mid-foot, a characteristic of weakness of the longitudinal arch (mid-tarsal loading).

Diabetes is Increasing in Prevalence

Barry J. Goldlist, MD, FRCPC, FACP

Our theme for this first issue of the new millennium is diabetes mellitus in the elderly. It is an appropriate topic because there are two main factors driving the increase in the numbers of patients with diabetes; these are the aging of the population, and the increasing prevalence of obesity. Unfortunately, particularly in the 'young old' these two factors frequently coexist.

Diabetes, like many other chronic disorders, results from a combination of both genetic and environmental factors. The major environmental factor is the increasing obesity of our population, but the genesis of that obesity is very complex. Two of the factors involved are changing dietary patterns and decreased physical activity. As in most diseases, prevention is the most effective treatment. However, improving eating habits and increasing physical activity is not easy to achieve in large populations, particularly when cars and fast foods are omnipresent.

Diabetes mellitus is a major risk factor for renal failure and vascular disease in the elderly; yet, despite much evidence to the contrary, physicians are often hesitant to aggressively treat this population. At times, this might be the correct course, but often the hesitancy is based on misconceptions concerning life expectancy at various ages. A healthy 70-year-old woman has a life expectancy of about 17 years, or more than 20% of her entire life! Even at age 80, a healthy woman has 7-8 years of life expectancy ahead, or 10% of her life. These are substantial periods of time, and suggest that treatment to prevent further complications of diabetes is very well warranted. In fact, the same holistic approach to diabetes management that is used in younger patients is appropriate for many older diabetics, particularly that group of 'young old' aged 65-75.

This holistic approach includes paying detailed attention to all known risk factors. There is excellent evidence that effective blood pressure control, lowering lipids, and the appropriate use of ACE inhibitors and beta-blockers, is effective for reducing cardiovascular risk in patients with diabetes. Tight glucose control, lowering triglycerides, and increasing HDL are more controversial strategies to prevent complications in elderly patients with diabetes. Of course, early attention to any complications (e.g. foot care, eye care) is also critical in maintaining quality of life.

This edition will address some of the acute complications of diabetes (by Daniel Tessier), foot care (Leslie Goldenberg) and diabetic retinopathy (Mark Mandelcorn). The most important issue for many elderly patients is learning about the disease and its dietary control, and Tess Montada-Atin has written an excellent article on this topic. As well as our usual pot pourri of columns, there are articles on peripheral vascular disease in the elderly, recent developments in the primary care of dementia (Serge Gauthier), the difficulties in prescribing for older people, and an article on ethics. Fittingly, for this edition, our article on the biology of aging is focussed on mechanisms of insulin resistance.

I hope you enjoy this edition.

Blindness is a Result of Diabetic Macular Edema

Mark Mandelcorn, MD, FRCS(C)
Vitreo-retinal Surgeon
Toronto Western Hospital 

It is astonishing that in the year 2000, nearly 80 years after the discovery of insulin, diabetes became the most common cause of blindness in North America. Everyone who looks after diabetics, therefore, has an important role to play in helping these patients reduce their risk of suffering the microvascular and macrovascular complications arising from diabetes. Recent clinical trials have once again confirmed the link between good blood sugar control and the reduced incidence of complications, such as blindness. Consequently, it is accepted that the first goal of treatment is optimum control not only of blood sugar but of other supervening problems, like hypertension, that may aggravate any existing complication, particularly diabetic retinopathy.

Diabetic retinopathy is said to occur in over 90% of type 1 diabetics (characterized by juvenile onset and insulin-dependence) and in a slightly lower percentage of type 2 diabetics (characterized by late onset and lack of insulin dependence). However, only about 25% of patients with diabetic retinopathy develop visual loss and only about 5% become blind.

Daniel Tessier, MD, MSc, FRCPC, CSPQ
Sherbrooke Geriatric University Institute
Associate Professor, Faculty of Medicine
University of Sherbrooke

Introduction
The most recent Health and Nutrition survey in the United States demonstrated that the prevalence of diabetes is approaching 20% in Caucasian patients over the age of 70, and in certain ethnic groups, may be as high as 50%.¹ Currently, the over 65 age group represents about 13 % of the total population, a percentage which is expected, by the year 2020, to increase to approximately 21% of the population. The majority of elderly diabetic patients have type 2 diabetes mellitus (DM), characterized by a gradually increasing glycemia that results from a combination of a resistance, at the cellular level, to the action of insulin, and a gradual decline of insulin secretion by the pancreas. A few years of asymptomatic disease may have elapsed prior to the diagnosis of DM being made, especially in the case of elderly patients. The following article will provide a brief review of the acute complications related to DM in the elderly with a particular focus on the evolution of the disease, side effects of treatment, and the vascular problems and acute infections that are often associated with this health problem.

Julia Krestow, BSc, MSc
Freelance writer
Geriatrics & Aging

It is perhaps not since Banting and Best's discovery of insulin in 1921, that a discovery in diabetic research has held such potential for the treatment of this crippling disease. In May of this year, the University of Alberta achieved instant fame when a research team, led by Dr. Ray Rajotte, announced that it had successfully freed seven diabetics from their daily insulin injections. The team, which consisted of Dr. Jonathan Lakey and Dr. Greg Korbutt, and also included the transplant surgeon Dr. James Shapiro, reported their results at the American Society of Transplant Surgeons and the American Transplantation Society in Chicago. Dr. Shapiro has succeeded in transplanting donor insulin-producing, pancreatic islet cells into seven people, all of whom had, prior to the study, required up to 15 self-injected insulin shots on a daily basis.

Diabetes affects more than 2.25 million Canadians and is subdivided into two categories; Type 1 diabetes is usually diagnosed in children and occurs when the pancreas is unable to produce insulin. Type II diabetes, which accounts for approximately 90% of the cases and usually develops in adulthood, occurs when the pancreas does not produce enough insulin or when the body does not use the insulin effectively.

Neil Fam, BSc, MSc

Diabetes is a common chronic disease characterized by metabolic abnormalities that have both acute and long term complications. In Canada, at least 1.5 million individuals (5% of the population) are afflicted by the disease, and this number is predicted to increase to 2.2 million by the year 2000. Diabetes has considerable associated morbidity and mortality. It is a major cause of coronary artery disease and stroke and is a leading cause of blindness and kidney disease in adults. Furthermore, individuals with diabetes have a shortened life expectancy when compared to those without the disease. Long-term complications occur in both type 1 and type 2 diabetes and result from the chronic hyperglycemia and hypertension associated with the disease. This article summarizes the chronic complications of diabetes, including effects on the vascular system, kidneys, eyes and nervous system.

The diabetic patient may develop one or all of a myriad of complications, including vascular disease, hypertension, retinopathy, nephropathy, neuropathy and foot disease.

Vascular Complications and Hypertension
The vascular complications of diabetes can be divided into microvascular and macrovascular disease.

D'Arcy Little, MD, CCFP
York Community Services, Toronto and
Department of Family Medicine, Sunnybrook Campus of Sunnybrook and Women's College Health Sciences Centre, Toronto, Ontario

Epidemiology
Diabetes mellitus, a metabolic disease characterized by hyperglycemia secondary to defective insulin secretion and/or action, is an extremely common, chronic illness with a high burden of potentially preventable complications. It is a leading cause of coronary artery disease, peripheral vascular disease, kidney failure, peripheral neuropathy and new-onset blindness. A full five percent of Canadians have been diagnosed with the disease, and this percentage is predicted to translate into 2.2 million cases by the year 2000. However, statistics from the United States suggest that for every person diagnosed with diabetes, another has the disease and remains undiagnosed. Appropriate screening for diabetes provides the means to identify those undiagnosed individuals who may benefit from earlier intervention.

The terms insulin-dependent (IDDM) and non-insulin-dependent (NIDDM) diabetes were eliminated in favour of the terms "Type 1" and "Type 2" diabetes in an effort to emphasize pathogenesis over treatment in disease diagnosis.