Hypoglycemia in patients with type 2 diabetes mellitus.

BACKGROUND Although hypoglycemia is the most common complication of intensive diabetes therapy, there is little information about risk factors for hypoglycemia in patients with type 2 diabetes mellitus. OBJECTIVE To determine the prevalence and predisposing factors for hypoglycemia in patients with type 2 diabetes. METHODS Retrospective, cross-sectional analysis set in an outpatient specialty diabetes clinic. We included those patients who had baseline and follow-up visits from April 1 through October 31, 1999. Hypoglycemia was defined as typical symptoms relieved by eating, and/or blood glucose level of less than 60 mg/dL (<3.3 mmol/L). Univariate and multivariate logistic regression were used to determine the contributions to hypoglycemia of age, sex, diabetes duration, body mass index (calculated as weight in kilograms divided by the square of height in meters), fasting plasma glucose level, glycosylated hemoglobin (HbA(1c)) level, type of therapy, and previous episodes at the follow-up visit. RESULTS We studied 1055 patients. Prevalence of hypoglycemic symptoms was 12% (9/76) for patients treated with diet alone, 16% (56/346) for those using oral agents alone, and 30% (193/633) for those using any insulin (P<.001). Severe hypoglycemia occurred in only 5 patients (0.5%), all using insulin. Multiple logistic regression analysis demonstrated that insulin therapy, lower HbA(1c) level at follow-up, younger age, and report of hypoglycemia at the baseline visit were independently associated with increased prevalence of hypoglycemia. There were no significant predictors of severe hypoglycemia. CONCLUSIONS Mild hypoglycemia is common in patients with type 2 diabetes undergoing aggressive diabetes management, but severe hypoglycemia is rare. Concerns about hypoglycemia should not deter efforts to achieve tight glycemic control in most patients with type 2 diabetes.