Hypoglycaemia in Clinical Diabetes

RISKS OF DEATH FROM HYPOGLYCAEMIA 267diabetic population (false negative result for a diagnosis of hypoglycaemia). Alternatively, thepathologist, even when unsure may attribute death to hypoglycaemia rather than indicatingno cause on a certificate (false positive).CRUDE ESTIMATES OF MORTALITY FROM HYPOGLYCAEMIABecause of the problems detailed above, any estimate of mortality from hypoglycaemiawill be crude. Published reports range from no deaths attributable to hypoglycaemia at oneextreme to between 20% and 25% in reports from some Scandinavian centres. Most studiessuggest that the proportion of deaths caused by hypoglycaemia is between 2% and 6%, alower frequency than those associated with ketoacidosis. For a more detailed analysis, thereader is referred to the review by Tattersall and Gale (1993).If deaths caused by renal failure or coronary heart disease in people with diabetes continueto decline as diabetes care improves, then the relative proportion of deaths caused byhypoglycaemia may increase. This is particularly likely if intensive insulin therapy continuesto be adopted more widely in an attempt to prevent or reduce microvascular disease (TheDCCT Research Group 1991; The Diabetes Control and Complications Trial ResearchGroup 1993).RISKS OF DEATH FROM HYPOGLYCAEMIAThe risk factors that are commonly cited as increasing the risk of death from hypoglycaemiaare often anecdotal, and may owe more to the prejudices of individual clinicians than to scientificevidence. Those suggested are detailed in Box 12.1 and include alcohol abuse and/orinebriation (Arky et al., 1968; Kalimo and Olsson, 1980; Critchley et al., 1984; MacCuish,1993), psychiatric illness or personality disorder (Shenfield et al., 1980; Tunbridge, 1981),self-neglect (Tunbridge, 1981), resistance to education (Shenfield et al., 1980), hypopituitarismfollowing pituitary ablation therapy for proliferative retinopathy (Nabarro et al.,1979; Shenfield et al., 1980), and patients who have diabetes secondary to pancreatic disease(MacCuish, 1993).Box 12.1Possible risk factors for death from hypoglycaemia• Alcoholism and/or inebriation• Psychiatric illness or personality disorder• Self-neglect; inanition• Fecklessness/resistance to education• Diabetes secondary to pancreatic disease• Hypopituitarism following pituitary ablation