High Glucose Variability Increases Mortality Risk in Hospitalized Patients.

CONTEXT

Glucose variability (GV) is common among hospitalized patients, but the prognostic implications are not understood.

OBJECTIVE

Investigate the association between GV, hospital length of stay (LOS), and mortality.

METHODS

GV was assessed by coefficient of variance (CV) and standard deviation (SD) of glucose values during hospitalization.

SETTING

Historical prospectively collected data of patients hospitalized between January 2011 and December 2013.

PATIENTS

Patients ≥18 years old.

MAIN OUTCOME

LOS, and in-hospital and mortality at end of follow-up.

RESULTS

The cohort included 20,303 patients (mean age ± SD, 70 ± 17 years; 51% men; median follow-up, 1022 days), of whom 8565 patients (42%) had diabetes mellitus (DM). Mean LOS was longer with higher CV or SD tertiles in patients without and with DM. In-hospital mortality was 8.2%, associated with higher tertiles of CV (4%, 10%, 19%) and SD (4%, 11%, 21%) in patients without DM and with DM (3%, 5%, 10%; and 2%, 4%, 9%, respectively). Mortality at the end of follow-up was increased in patients without DM with higher CV (28%, 42%, 55%) and SD (28%, 44%, 57%) tertiles and in patients with DM (26%, 35%, 45%; and 25%, 34%, 44%, respectively). Multivariate analysis indicated increased risk for in-hospital and end of follow-up mortality, in both groups. Adjustment for glucocorticoid treatment or hypoglycemia did not affect the results. Glucose levels during hospitalization and GV were two independent factors affecting LOS and in-hospital mortality. In each CV tertile, mortality was higher with median glucose ≥180 mg/dL, compared with <180 mg/dL.

CONCLUSIONS

In hospitalized patients with and without DM, increased GV is associated with longer hospitalization and increased short- and long-term mortality.