TYPE 2 diabetes is one of the fastest growing epidemics in human history. It is not a single disorder in terms of causation and is characterised by progressive pancreatic beta-cell failure.
While lifestyle measures, weight loss and exercise should always be considered as the first-line treatment, these succeed in a limited number of patients. Pharmacological intervention with blood glucose lowering agents is almost always needed.
The multiplicity of causal metabolic defects involved in type 2 diabetes makes it unrealistic to expect that most people with diabetes will, over time, achieve excellent blood glucose control with any single oral hypoglycaemic agent or any combination of agents.
As the progressive nature of type 2 diabetes requires ongoing assessment of metabolic control, intensification of therapy with increasing doses of oral hypoglycaemic agents then a requirement for insulin is not unusual.
Paradoxically, the main recommended plans (algorithms) for treatment, such as the one from the American Diabetes Association and European Association for The Study of Diabetes, may actually set us up for therapeutic failure. Each new recommendation suggested by these algorithms is a result of failure of the previous step.
The clinical pathway finally ends with the administration of insulin, often combined with one or more oral hypoglycaemic agents. A frequent outcome of insulin therapy is weight gain. Obviously, this is counterintuitive for the treatment of patients with type 2 diabetes.
A recent review and meta-analysis in the Canadian Medical Association Journal addressed the issue of initiating insulin in patients with type 2 diabetes. One of its key recommendations is that insulin should be considered early in the course of treatment.
However, experience from North America and the UK in managing type 2 diabetes may differ to that of Australian diabetologists, and many of us are not so “trigger happy” to move to insulin early. It is a subject being debated widely.
Few diabetologists would claim that our present management of type 2 diabetes (and, indeed, type 1 diabetes) is ideal.
In type 1 diabetes, there is absolute insulin deficiency, and multiple daily injections are needed — a basal dose of long-acting insulin and an injection of short-acting insulin before each meal. This regimen attempts to replicate the normal pancreatic response consisting of a continuous basal release of insulin with bursts at each meal in response to food.
Increasingly in patients with type 2 diabetes, as a result of both physician and patient failures to perfect treatment, we are seeing a quick move to insulin therapy. This is often before an adequate analysis of the situation is made, and other options explored.
Decades of managing type 2 diabetes lead me to agree with the list of barriers to initiation of insulin cited by the Canadian authors, ie, fear of hypoglycaemia, the pain from frequent blood testing, weight gain, fear of injections and the associated pain.
Now, while these are important issues for the patient, and often affect the physician’s judgement, it is important to treat every person individually.
Type 2 diabetes is characterised by two key features — pancreatic beta-cell failure and insulin resistance — and the balance between these two varies in individuals, so the natural history of diabetes and its treatment will vary. For example, a person with predominant beta-cell failure may be likely to require insulin earlier in their course of treatment than someone with predominant insulin resistance.
It is very clear that, in a patient with recent onset type 2 diabetes who has lost weight and who has significant and symptomatic hyperglycaemia, insulin should be the first line of treatment. However, there is a large gap between this scenario and the usual presentation of type 2 diabetes, which is often asymptomatic and discovered accidentally.
The jury is still out on the benefits of early institution of insulin in type 2 diabetes, so the debate will continue.
In the meantime, practitioners should promote lifestyle measures and optimal use of oral hypoglycaemic agents. If these measures fail, judicious use of insulin should be considered, and it can often be done as an adjunct to oral agents.
Insulin is safe and can be effective, but each person with type 2 diabetes should receive education and be assessed carefully, considering their compliance to a regimen that requires long-term commitment.
Professor Paul Zimmet is director emeritus of the Baker IDI Heart and Diabetes Institute.
The author has acted as an adviser for Lilly, Novo Nordisk and sanofi Aventis.
Posted 28 May 2012