In a study of adult patients at Massachusetts General Hospital in Boston, nearly one in five had blood test results suggesting they had unrecognized diabetes, investigators report in the Journal of Clinical Endocrinology and Metabolism.

“Screening with HbA1c levels, (a measure of blood sugar levels over several weeks), at the time of admission to an acute care hospital may represent an opportunity to identify a high-risk group of patients with unrecognized diabetes and, if coupled with effective follow-up, to promote prevention of subsequent diabetes-related complications,” Dr. Deborah J. Wexler and associates conclude.

Their study included 695 patients admitted during 11 days in the summer of 2006. Twenty percent had previously diagnosed diabetes.

Eighteen percent of patients had high HbA1c levels but with no diabetes diagnosis in their charts, a rate that is “roughly 5-fold higher than in the general outpatient population,” the investigators report.

However, with standard blood sugar tests, which only measure levels in the last few hours, the patients with undiagnosed diabetes were no more likely than non-diabetic patients to exhibit high sugar levels.

“Random glucose levels, accordingly, were insensitive and nonspecific for the diagnosis of diabetes” in hospitalized patients, Wexler’s team report.

Only 15 percent of surviving patients who were followed up within the hospital-affiliated healthcare system were diagnosed with diabetes during the subsequent year.

“Consequently,” the researchers state, “the utility of diagnosis for inpatients is likely to be low unless patients subsequently receive long-term outpatient care to prevent complications of diabetes.”

SOURCE: Journal of Clinical Endocrinology and Metabolism, November 2008.