Risk Factors for Hypoglycemic Coma: A Study of 33 Patients on Insulin Therapy Who Were Transported to the Hospital by Ambulance

OBJECTIVE: Patients on outpatient insulin therapy are at a high risk of severe hypoglycemia and a high incidence of hypoglycemic coma. However, only a few studies have explored the risk factors for hypoglycemic coma in such patients. We retrospectively analyzed the clinical characteristics of diabetic patients who had developed hypoglycemic coma during outpatient insulin therapy. METHODS: This study included 33 diabetic patients on insulin therapy who were transported to the hospital by ambulance for severe hypoglycemia. Patients with a Japan Coma Scale score ＜100 were classified as the non-coma group (n=18), while those with a score ≥100 (n=15) were classified into the coma group. RESULTS: Patients in the coma group were significantly older, with a higher proportion of elderly patients ( ≥65 years of age), than those in the non-coma group. Although no marked difference in the basal insulin dose was observed between the two groups, the bolus insulin dose was significantly higher in the coma group. However, no marked differences in the disease type or renal function were noted between the two groups. CONCLUSION: An advanced age and bolus insulin dose are risk factors for hypoglycemic coma in diabetic patients on insulin therapy. Bolus insulin dose minimization should be performed in order to prevent hypoglycemic coma, especially in elderly diabetic patients.