Abstracts

Untangling glycaemia and mortality in critical care

by JG Chase




Institution: University of Canterbury
Department:
Year: 2017
Keywords: Critical care; Hyperglycaemia; Glycaemic control; Blood glucose; Variability; Insulin sensitivity; Insulin; Field of Research::11 - Medical and Health Sciences::1103 - Clinical Sciences::110310 - Intensive Care; Field of Research::11 - Medical and Health Sciences::1103 - Clinical Sciences::110306 - Endocrinology
Posted: 02/01/2018
Record ID: 2197639
Full text PDF: http://hdl.handle.net/10092/14584


Abstract

Hyperglycaemia is associated with adverse outcomes in the intensive care unit, and initial studies suggested outcome benefits of glycaemic control (GC). However, subsequent studies often failed to replicate these results, and they were often unable to achieve consistent, safe control, raising questions about the benefit or harm of GC as well as the nature of the association of glycaemia with mortality and clinical outcomes. In this study, we evaluated if non-survivors are harder to control than survivors and determined if glycaemic outcome is a function of patient condition and eventual outcome or of the glycaemic control provided.Clinically validated, model-based, hour-to-hour insulin sensitivity (SI) and its hour-to-hour variability (%SI) were identified over the first 72 h of therapy in 145 patients (119 survivors, 26 non-survivors). In hypothesis testing, we compared distributions of SI and %SI in 6-hourly blocks for survivors and non-survivors. In equivalence testing, we assessed if differences in these distributions, based on blood glucose measurement error, were clinically significant.SI level was never equivalent between survivors and non-survivors (95% CI of percentage difference in medians outside 12%). Non-survivors had higher SI, ranging from 9% to 47% higher overall in 6-h blocks, and this difference became statistically significant as glycaemic control progressed. %SI was equivalent between survivors and non-survivors for all 6-hourly blocks (95% CI of difference in medians within 12%) and decreased in general over time as glycaemic control progressed.Whereas non-survivors had higher SI levels, variability was equivalent to that of survivors over the first 72 h. These results indicate survivors and non-survivors are equally controllable, given an effective glycaemic control protocol, suggesting that glycaemia level and variability, and thus the association between glycaemia and outcome, are essentially determined by the control provided rather than by underlying patient or metabolic condition.