Clinical characterisation of severe hypoglycaemia--a prospective population-based study.

AIM

To determine the clinical characteristics of severe hypoglycaemia (SH) in a nonselected German population. SH was defined as an event requiring intravenous glucose or glucagon injection.

METHODS

The prospective population-based study screened sensitively for SH in a region with 200,000 inhabitants between 1997 and 2000. All 30,768 patients who presented to the regional central hospital emergency department, and 6,631 (85 %) of 7,804 patients attended by the emergency medical service in the region were given an initial blood glucose test to detect atypical hypoglycaemia.

RESULTS

Altogether, 264 cases of SH were registered, which occurred either spontaneously (n = 14; 5 %), in subjects with type 1 (n = 92; 35 %) or type 2 diabetes (n = 148; 56 %), or in subjects with a non-classified form of diabetes (n = 10; 4 %). On the basis of the estimated local number of diabetic patients the annual rate of SH was 1.5 episodes per 100 patients in insulin-treated type 2 diabetics compared with a rate of 0.4 episodes per 100 patients for the overall group of type 2 diabetic patients. Nocturnal hypoglycaemia accounted for 44 % of episodes in patients with type 1 diabetes on intensified therapy but for only 25 % in patients with type 2 diabetes. 26 % of the hypoglycaemic individuals with type 1 diabetes had an impaired awareness of hypoglycaemia and thus recurrent hypoglycaemic episodes. Irrespective of the treatment, the most frequent contributing factors for SH in type 2 diabetic patients were advanced age (76 +/- 12 years), multimorbidity (3.6 +/- 2.6 concomitant diseases)--in particular renal impairment (54 % [80/148])--and polypharmacy (4 +/- 2.7 concomitant drugs). 34 % (50/148) of the subjects with type 2 diabetes lived in nursing homes or were cared for by a home nursing service. With standardised treatment zero mortality of SH in diabetic patients was achieved, only one non-diabetic died due to hepatic failure.

CONCLUSION

In elderly, multimorbid patients approaching the insulin-deficient end of the spectrum of type 2 diabetes the risk of developing SH increases considerably, nearing that in patients with type 1 diabetes. In order to avoid SH in geriatric patients, the treatment targets should be defined critically, taking into account individual quality of life and life expectancy. Hypoglycaemia unawareness is a major risk factor for SH in type 1 diabetes.