Figure 1. Association Between Inpatient Blood Glucose Recordings and Preadmission Outpatient Hemoglobin A_1c Level.

Preadmission hemoglobin A_1c was measured using most recent hemoglobin A_1c laboratory value collected within 1 year preceding hospitalization. Inpatient blood glucose control was defined by the number of elevated blood glucose recordings as severely elevated (≥3 recordings of ≥300 mg/dL [to convert to millimoles per liter, multiply by 0.0555]), moderately elevated (≥3 recordings of ≥200 mg/dL without meeting criteria for severely elevated), or not elevated. Preadmission hemoglobin A_1c was found to be associated with inpatient blood glucose categories (P < .001 using a χ² test). To convert hemoglobin A_1c to proportion of total hemoglobin, multiply by 0.01.