Hypoglycaemia in Clinical Diabetes

184 RISKS OF STRICT GLYCAEMIC CONTROLto improve their glycaemic control, especially with modern techniques that are able to deliverimproved control without increasing hypoglycaemia risk.In practice, however, there are patients in whom attempts to achieve a near normal glycatedhaemoglobin are not appropriate (Box 8.2). Patients with advanced complications, especiallyretinopathy, have not been shown to benefit and a sudden improvement in glycaemic controlmay cause acceleration in severity of pre-proliferative or early proliferative retinopathy(Hanssen et al., 1986). Although some authorities claim that this should not be a contraindicationto improving glycaemic control (Chantelau and Kohner, 1997), as yet there is no realevidence for benefit in advanced cases and the retinopathy should be treated appropriatelybefore glycaemic control is intensified. Similarly, in patients with established renal impairmentand severe macrovascular disease, attempts to treat elevated blood pressure and plasmalipids and to encourage patients to stop smoking may be more beneficial than targetingglycaemic control alone. As intensive insulin therapy is aimed at achieving benefit over aperiod of five to ten years or more, patients with a reduced life expectancy should not beexposed to the risks and rigours associated with this treatment regimen. This applies also toelderly patients, who may be frail and physically inactive.Very young patients may not be good candidates for very strict glycaemic control. Poorcontrol should not be encouraged in children, as growth may be jeopardised, and there issome evidence that pre-pubertal glycaemic control may influence the later risk of complications(Donaghue et al., 1997; Holl et al., 1998). However, very small children, who arevery insulin-sensitive, may be at risk of intellectual damage if exposed to recurrent severehypoglycaemia (see Chapters 9 and 13).Box 8.2Application of strict glycaemic control in type 1 diabetesCaution required:• Long duration of insulin-treated diabetes (counterregulatory deficiences).• Previous history of severe hypoglycaemia.• Established impaired awareness of hypoglycaemia.• History of epilepsy.• Patient unwilling to do home blood glucose monitoring.Contraindicated:• Extremes of age.• Ischaemic heart disease.• Unstable diabetic retinopathy (can be instituted after treatment).• Advanced diabetic complications.• Limited life expectancy (e.g. serious coexisting disease).