Hypoglycemia in hospitalized patients treated with sulfonylureas.

STUDY OBJECTIVE: To identify the incidence of and risk factors associated with hypoglycemia in hospitalized patients taking sulfonylureas.

DESIGN: Nested case-control study.

SETTING: Tertiary care academic medical center.

PATIENTS: Adults who received a sulfonylurea during hospitalization between November 1, 2008, and October 31, 2009. Case patients were those who experienced at least one episode of hypoglycemia, defined as a blood glucose level less than 70 mg/dl; potential control patients were those who did not experience hypoglycemia. One hundred seventeen cases were matched in a 1:1 ratio with controls based on sex and the number of days treated with a sulfonylurea in the hospital. For case patients, the index date was defined as the date of first blood glucose level less than 70 mg/dl. The number of days that the patient was taking the sulfonylurea before the index date was determined, and this same number was used to define the index date for the matched controls.

MEASUREMENTS AND MAIN RESULTS: Overall, 19% of patients who received a sulfonylurea experienced at least one episode of hypoglycemia: 22% receiving glyburide, 19% receiving glimepiride, and 16% receiving glipizide. Variables included in the multivariate regression were age 65 years or older, glomerular filtration rate (GFR)≤ 30 ml/min/1.73 m(2) , and treatment with glipizide, glyburide, or concurrent intermediate- or long-acting insulin. Age 65 years or older (odds ratio [OR] 3.07, p < 0.001), intermediate- or long-acting insulin (OR 3.01, p=0.002), and GFR of 30 ml/minute/1.73 m(2) or lower (OR 3.64, p=0.006) were predictors of hypoglycemia. Cases were less likely than controls to receive glipizide (OR 0.44, p=0.005).

CONCLUSION: Hospitalized patients at increased risk for sulfonylurea-related hypoglycemia were those aged 65 years or older, those with a GFR of 30 ml/minute/1.73 m(2) or lower, and those who received concurrent intermediate- or long-acting insulin during inpatient sulfonylurea therapy. Sulfonylureas should be avoided or used with caution in these patients.