Hypoglycemia may be increased by inpatient meal timing

Most episodes of inpatient hypoglycemia occurred between 9 p.m. and 9 a.m., one British hospital found in an analysis of hospitalized patients with diabetes.

Researchers did snapshot audits to capture all hypoglycemic results in inpatients receiving insulin or a sulfonylurea on two different days, six weeks apart. They identified a total of 109 patients who were hospitalized for at least 24 hours. For those patients who were hospitalized longer than a week, they reviewed only the last seven days' blood glucose logs. The researchers then compared the results of this snapshot audit with blood sugar measurements from all similar inpatients from a two-month period stored in a Web database (more than 15,000 blood glucose readings). Hypoglycemia was defined as severe if blood glucose was below 3.0 mmol/L (54 mg/dL) and mild if it was between 3.0 and 3.9 mmol/L (54 to 70 mg/dL). Results were published by Diabetic Medicine on June 29.

According to the bedside audit, 74% of the hospital's patients had a hypoglycemic event, and 83% of the events occurred between 9 p.m. and 9 a.m. Seventy percent of the severe hypoglycemia results were in this time period. The database showed similar timing: 771 hypoglycemic test results (4.9% of the total), 70% of them at night. Forty percent of the episodes were severe, and those mostly (66%) occurred between 9 p.m. and 9 a.m.

Inpatient hypoglycemia occurs more frequently between these hours, the study authors concluded, noting that their results may actually underestimate the phenomenon since glucose testing is less frequent overnight. The hypoglycemia may result from insufficient carbohydrate intake during the time period, because the hospital serves no food between the evening meal at 5 p.m. and breakfast at 8:30 a.m., they speculated.

To confirm this supposition, the authors also surveyed 18 diabetes inpatient nurses from other English hospitals and found that 14 nurses reported more hypoglycemia at night, and 12 of those said that bedtime snacks were never or only sometimes available to patients. Of the four that didn't report more hypoglycemia at night, three worked at hospitals where a snack was always available. The study authors planned to address the issue of prolonged fasting at their own hospital and suggested that other hospitals or clinicians similarly investigate their hypoglycemia trends and snack policies.