Introduction: This study examines the likelihood and evolution of overall and hypoglycemia-inducing
variability of insulin sensitivity in ICU patients based on diagnosis and day of stay.
Materials and Methods: An analysis of model-based insulin sensitivity for patients
in a medical ICU (Christchurch, New Zealand). Two metrics are defined to measure the
variability of a patient's insulin sensitivity relative to predictions of a stochastic
model created from the same data for all patients over all days of stay. The first
selectively captures large increases related to the risk of hypoglycemia. The second
captures overall variability. Distributions of per-patient variability scores were
evaluated over different ICU days of stay and for different diagnosis groups based
on APACHE III: operative and non-operative cardiac, gastric, all other. Linear and
generalized linear mixed effects models assess the statistical significance of differences
between groups and over days.
Results: Variability defined by the two metrics was not substantially different. Variability
was highest on day 1, and decreased over time () in every diagnosis group. There were
significant differences between some diagnosis groups: non-operative gastric patients
were the least variable, while cardiac (operative and non-operative) patients exhibited
the highest variability.
Conclusions: This study characterizes the variability and evolution of insulin sensitivity
in critically ill patients, and may help inform the clinical management of metabolic
dysfunction in critical care.
