Management of obesity in non-insulin-dependent diabetes mellitus

Abstract

Obesity is common in non-insulin-dependent diabetes mellitus (NIDDM) patients; in Singapore in a cohort of 314 diabetics, 44.3% were overweight. Management of obesity in diabetics differs from that in non-diabetics in that it is more urgent; weight maintenance is more difficult and hypoglycaemic medication may cause weight changes. However, like in the non-diabetic, management of obesity in the diabetic requires a pragmatic and realistic approach. A team approach is required: the help of a nurse educator, a dietitian, behaviour modification therapist, exercise therapist and others are required. A detailed history, careful physical examination and relevant investigations are required to assess the severity of the diabetic state and to exclude an occasional underlying cause of the obesity in the obese NIDDM patient. Weight loss is urgent in the obese NIDDM patient, especially for those with android obesity. There must be a reduction in energy intake. Weight loss leads to an improvement in glucose tolerance and in insulin sensitivity, as well as to a reduction in lipid levels and to a fall in blood pressure in the hypertensive. Exercise is of limited short-term value measured in terms of weight reduction, except in the younger obese NIDDM patient; but it does allow improvement in overall metabolic control and, long-term, is critical for preferred weight maintenance. The biguanide, Metformin, is the hypoglycaemic drug of choice as it leads to consistent weight reduction. The sulphonylureas may cause weight gain. Insulin should be avoided where possible as it causes further weight gain. Other hypoglycaemic agents include Glucobay (alpha-glucosidase inhibitor) and Troglitazone (insulin sensitizer) which do not alter the weight. Orlistat (lipase inhibitor) is promising as it causes reduction of weight, blood glucose and lipid levels. Anti-obesity drugs (noradrenergic and serotonergic agents) have modest effects on weight reduction in the obese NIDDM patient; a widely-used preparation, Dexfenfluramine (Adifax), has been withdrawn because of side-effects. Surgery such as gastric plication is the last resort in treating the morbidly obese NIDDM patient. Against this background, the institution of life-long food and exercise habits which favour health, body composition and fat distribution are paramount in the prevention and minimization of expression of NIDDM. The discovery of leptin in 1994 has led to intense research into energy homeostasis in obesity; hopefully this will lead to better treatment of obesity in diabetics and non-diabetics.