Association of Glucose Concentrations at Hospital Discharge With Readmissions and Mortality: A Nationwide Cohort Study

Context Low blood glucose concentrations during the discharge day may affect 30-day readmission and posthospital discharge mortality rates. Objective To investigate whether patients with diabetes and low glucose values during the last day of hospitalization are at increased risk of readmission or mortality. Design and Outcomes Minimum point of care glucose values were collected during the last 24 hours of hospitalization. We used adjusted rates of 30-day readmission rate, 30-, 90-, and 180-day mortality rates, and combined 30-day readmission/mortality rate to identify minimum glucose thresholds above which patients can be safely discharged. Patients and Setting Nationwide cohort study including 843,978 admissions of patients with diabetes at the Veteran Affairs hospitals 14 years. Results The rate ratios (RRs) increased progressively for all five outcomes as the minimum glucose concentrations progressively decreased below the 90 to 99 mg/dL category, compared with the 100 to 109 mg/dL category: 30-day readmission RR, 1.01 to 1.45; 30-day readmission/mortality RR, 1.01 to 1.71; 30-day mortality RR, 0.99 to 5.82; 90-day mortality RR, 1.01 to 2.40; 180-day mortality RR, 1.03 to 1.91. Patients with diabetes experienced greater 30-day readmission rates, 30-, 90- and 180-day postdischarge mortality rates, and higher combined 30-day readmission/mortality rates, with glucose levels <92.9 mg/dL, <45.2 mg/dL, 65.8 mg/dL, 67.3 mg/dL, and <87.2 mg/dL, respectively. Conclusion Patients with diabetes who had hypoglycemia or near-normal glucose values during the last day of hospitalization had higher rates of 30-day readmission and postdischarge mortality.