Clinical characteristics of type 1 diabetic patients with and without severe hypoglycemia

To investigate the frequency of severe hypoglycemia (SH) and hypoglycemic coma and to identify clinical and behavioral risk indicators in a nonselected population of type 1 diabetic patients.

This study involved a retrospective clinical survey of 195 consecutive patients using a questionnaire addressing the frequency of SH (i.e., help from others required) and hypoglycemic coma during the previous year, general characteristics, behavior, hypoglycemia awareness, and the Hypoglycemia Fear Survey Data regarding diabetes, treatment, long-term complications, comorbidity, and comedication were obtained from the patients' medical records.

A total of 82% of subjects were receiving intensive insulin treatment, and mean +/- SD HbA(1c) was 7.8 +/- 1.2%. Mean duration of diabetes was 20 +/- 12 years. The occurrence of SH (including hypoglycemic coma) was 150 episodes/100 patient-years and affected 40.5% of the population. Hypoglycemic coma occurred in 19% of subjects (40 episodes/100 patient-years). SH without coma was independently related to nephropathy (odds ratio [OR] 4.8 [95% CI 1.5-15.1]), a threshold for hypoglycemic symptoms of <3 mmol/l (4.8 [1.8-12.0]), and a daily insulin dose 0.1 U/kg higher (1.3 [1.0-1.6]) (all ORs were adjusted for diabetes duration and use of comedication). Hypoglycemic coma was independently related to neuropathy (3.9 [1.5-10.4]), (nonselective) beta-blocking agents (14.9 [2.1-107.4]), and alcohol use (3.5 [1.3-9.1]) (all ORs were adjusted for diabetes duration).

SH and hypoglycemic coma are common in a nonselected population with type 1 diabetes. The presence of long-term complications, a threshold for symptoms of <3 mmo/l, alcohol use, and (nonselective) beta-blockers were associated with SH during the previous year. If prospectively confirmed, these results may have consequences for clinical practice.