Insulin treatment in elderly patients with non-insulin-dependent diabetes mellitus. A double-edged sword?

Abstract

Elderly patients with non-insulin-dependent (type 2) diabetes mellitus (NIDDM) form one of the largest sectors of the diabetic population. Emerging evidence indicates that hyperglycaemia is associated not just with an increased risk of microvascular complications but also with macrovascular disease, which remains the main cause of excess mortality in people with NIDDM. The treatment of hyperglycaemia in patients with NIDDM is notoriously difficult when diet, exercise and judicious use of oral antihyperglycaemic agents fail to maintain acceptable metabolic control. The treatment of hyperglycaemia in elderly patients is further hampered by age- or disease-related comorbidity. Insulin therapy can ameliorate many metabolic abnormalities of NIDDM, with consequent reduction of hyperglycaemia. Moreover, insulin treatment induces antiatherogenic changes in serum lipids and lipoproteins and probably enhances general well-being. However, insulin therapy is associated with bodyweight gain and an increased risk of hypoglycaemia. An unresolved question is the relationship of exogenous insulin therapy to the development of cardiovascular diseases. This reverse side of the coin has prompted research aimed at establishing methods to achieve the best possible reduction in hyperglycaemia with the smallest dose of insulin as possible. The most promising target in this respect has been the control of glucose overproduction from the liver by the nocturnal administration of intermediate- or long-acting insulin with or without oral antihyperglycaemic drugs. Intensive insulin therapy does not seem to have clear-cut benefits in elderly patients and can be hazardous. However, we cannot at present predict who will benefit from the various therapeutic regimens and therefore clinicians should use sound clinical judgment in choosing the appropriate therapy for an individual patient with NIDDM. Although we do not know at present whether we can, by our current modes of treatment, lower the frequency of vascular diseases, therapeutic nihilism, even in elderly patients with NIDDM, is outmoded.