Increased postoperative glucose variability is associated with adverse outcomes following orthopaedic surgery.
Aims
The aim of this study was to examine the association between postoperative glycaemic variability and adverse outcomes following orthopaedic surgery.


Patients and Methods
This retrospective study analyzed data on 12 978 patients (1361 with two operations) who underwent orthopaedic surgery at a single institution between 2001 and 2017. Patients with a minimum of either two postoperative measurements of blood glucose levels per day, or more than three measurements overall, were included in the study. Glycaemic variability was assessed using a coefficient of variation (CV). The length of stay (LOS), in-hospital complications, and 90-day readmission and mortality rates were examined. Data were analyzed with linear and generalized linear mixed models for linear and binary outcomes, adjusting for various covariates.


Results
The cohort included 14 339 admissions, of which 3302 (23.0%) involved diabetic patients. Patients with CV values in the upper tertile were twice as likely to have an in-hospital complication compared with patients in the lowest tertile (19.4% versus 9.0%, p < 0.001), and almost five times more likely to die compared with those in the lowest tertile (2.8% versus 0.6%, p < 0.001). Results of the adjusted analyses indicated that the mean LOS was 1.28 days longer in the highest versus the lowest CV tertile (p < 0.001), and the odds of an in-hospital complication and 90-day mortality in the highest CV tertile were respectively 1.91 (p < 0.001) and 2.10 (p = 0.001) times larger than the odds of these events in the lowest CV tertile. These associations were significant even for non-diabetic patients. After adjusting for hypoglycaemia, the relationships remained significant, except that the CV tertile no longer predicted mortality in diabetics.


Conclusion
These results indicate that higher glycaemic variability is associated with longer LOS and in-hospital complications. Glycaemic variability also predicted death, although that primarily held for non-diabetic patients in the highest CV tertile following orthopaedic surgery. Prospective studies should examine whether ensuring low postoperative glycaemic variability may reduce complication rates and mortality. Cite this article: Bone Joint J 2018;100-B:1125-32.
['Shohat|N|N|', 'Foltz|C|C|', 'Restrepo|C|C|', 'Goswami|K|K|', 'Tan|T|T|', 'Parvizi|J|J|']
D000368:Aged D001786:Blood Glucose D048909:Diabetes Complications D005260:Female D006442:Glycated Hemoglobin A D017052:Hospital Mortality D006801:Humans D006943:Hyperglycemia D007902:Length of Stay D008297:Male D008875:Middle Aged D019637:Orthopedic Procedures D010359:Patient Readmission D011182:Postoperative Care D011183:Postoperative Complications D012189:Retrospective Studies D012307:Risk Factors
Glucose Glucose variability Complications Glycated haemoglobin Glycemic control