Accidents in patients with insulin-treated diabetes: increased risk of low-impact falls but not motor vehicle crashes--a prospective register-based study.

BACKGROUND: Patients with diabetes mellitus may be at increased risk of accidents, mainly because of hypoglycemia. A variety of approaches have been adopted in an attempt to quantify this risk, but there has not been, to date, a systematic study using a national trauma register. In this study, we report findings from the Scottish Trauma Audit Group database.
METHODS: The database includes all patients admitted to hospital for 3 or more days, or who died in hospital as a result of their accident. The study includes 11,244 cases aged 15 years or over entered into the database between July 1996 and June 1998. This included 151 patients with insulin-treated diabetes. Using detailed prescribing information from one representative region, we have calculated the rates of different types of accidents for patients treated with insulin and compared this with the control population. We have analyzed information on the mechanism and severity of injury, outcome, and length of hospital stay.
RESULTS: Overall, the rate of accidents for insulin-treated patients was estimated at 291.2 per 100,000 population per year compared with 148.4 for the control population (p < 0.001; relative risk, 1.97; 95% confidence interval, 1.68-2.32). Insulin-treated patients were, on average, older (p < 0.005), more likely to be women (p < 0.02), and had longer stay in hospital (p < 0.001). The major excess of injuries related to low falls (< 2 m), which accounted for 62.3% of the injuries in the insulin-treated group compared with 47.1% in the remainder (p < 0.01). Low falls in the insulin-treated group (n = 94) were examined in detail: compared with the control population, there was no difference in age and sex, Injury Severity Score, Revised Trauma Score (a measure of the severity of physiologic disturbance), or calculated probability of survival (TRISS). Length of inpatient stay was higher in the insulin-treated low-fall patients (10 vs. 7 days, p < 0.01). Of the 151 catalogued injuries, the vast majority were fractures at peripheral sites. Only 23 insulin-treated individuals were admitted after a motor vehicle crash during the study period. This represents a slight but not significant increase above the rate for the background population.
CONCLUSION: This study confirms that patients taking insulin are at increased risk of accidents. Among the different types of injury, only low-impact falls were significantly increased. This is most likely related to an increased tendency for insulin-treated patients to fall during a hypoglycemic episode. However, patients with diabetes may also be at higher risk of sustaining a fracture after a fall. The number of car crashes involving drivers with insulin-dependent diabetes is small, and the rate is not significantly greater than that of the background population. Further study of the causes and consequences of falls in diabetic patients is warranted.