Utility of HbA1c Levels for Diabetes Case Finding in Hospitalized Patients With Hyperglycemia

Abstract

OBJECTIVE -We evaluated the role of a single measurement of HbA 1c in a diabetes case finding in hospitalized patients with random hyperglycemia at admission. RESEARCH DESIGN AND METHODS -From 20March to 31 July 2000, 508 patients admitted through the emergency department of one hospital were tested for random hyperglycemia (plasma glucose [PG] Ͼ125 mg/dl). Consenting patients with hyperglycemia (without preexisting diabetes or on corticosteroids) underwent testing for HbA 1c levels, two fasting PG levels, and an outpatient oral glucose tolerance test (OGTT) if necessary.RESULTS -Of the patients, 50 (9.8%) met the inclusion criteria. Of these, 70% (n ϭ 35) completed the study, and 60% (n ϭ 21) were diagnosed with diabetes. Patients with diabetes had higher HbA 1c levels than subjects without diabetes (6.8 Ϯ 0.4 vs. 5.3 Ϯ 0.1%, P ϭ 0.002). An HbA 1c level Ͼ6.0% was 100% specific (14/14) and 57% sensitive (12/21) for the diagnosis of diabetes. When a lower cutoff value of HbA 1c at 5.2% was used, specificity was 50% (10/21) and sensitivity was 100% (7/14). CONCLUSIONS -In acutely ill patients with random hyperglycemia at hospital admission, an HbA 1c Ͼ6.0% reliably diagnoses diabetes, and an HbA 1c level Ͻ5.2% reliably excludes it (paralleling the operating characteristics of the standard fasting glucose measurements); however, the rapidity of the HbA 1c level can be useful for diabetes case finding and treatment initiation early in the hospital course.

Evaluation of hospital glycemic control at US Academic Medical Centers

“…25 We found wide variation among hospitals (range, 12.1%-76.5%) in use of recommended regimens of insulin therapy, defined as short-acting and long-acting subcutaneous insulin or IV insulin infusion or insulin pump therapy on second measurement day. Endocrine/diabetes consultation was infrequent, only 9% of all patients were evaluated by an endocrinologist or diabetologist at any time during the hospitalization.…”

“…Also, measurement of A1C can be used for diabetes case-finding in hospitalized patients with hyperglycemia. 25 Previously unrecognized diabetes is a common finding in patients admitted with cardiovascular disease. In a study of patients admitted with myocardial infarction, 25% were found to have previously undiagnosed diabetes.…”

Bridge over troubled waters: Safe and effective transitions of the inpatient with hyperglycemia

“…No ADA diagnostic thresholds for the HbA1c currently exist, but it can be a useful marker in making this distinction. 56 Among patients with new hyperglycemia, an HbA1c of 6% or greater was 100% specific for predicting a future diagnosis of diabetes in the small prospective cohort study by Greci et al, 57 but many endocrinologists use a cutoff of 7%. For all hyperglycemic patients, lifestyle interventions that promote weight loss and increased activity levels should be encouraged.…”

Management of Hyperglycemia in Critical Illness: Review of Targets and Strategies

“…Targets ranging from 120-250 mg!dl [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] have been advocated.…”

“…Approximately 12% of all hyperglycemic patients being admitted to tertiary care setting have no previous diagnosis of diabetes [6]. Sixty percent of patients with admission hyperglycemia developed confirmed diabetes at one year in a small study [7].…”