Association of blood glucose levels with in-hospital mortality and 30-day readmission in patients undergoing invasive cardiovascular surgery

Abstract

Objective:

This study aimed to evaluate the association of mean and maximum blood glucose (BG) levels with in-hospital mortality and 30-day hospital readmission among patients in the intensive care unit (ICU) undergoing invasive cardiovascular (CV) surgery.

Research design and methods:

The retrospective database analysis consisted of data from 3132 patients from 17 hospitals who underwent an invasive CV surgery during 1/2000–12/2006. Patients with hyperglycemia were identified based on serum BG levels recorded from 12 hours prior to and 24 hours after ICU admission. Separate logistic regression models were used to examine the association of mean and maximum BG levels to in-hospital mortality and 30-day readmission, adjusting for patient demographics, comorbidities and laboratory values.

Results:

The adjusted odds ratio (OR) for in-hospital mortality was 1.07 (95% CI: 1.01–1.12; p < .001) for every 0.56-mmol/L increase in mean BG, and OR = 1.06 (95% CI: 1.03–1.08, p < .001) for every 0.56-mmol/L increase in maximum BG. Mean BG was not associated with 30-day readmission while maximum BG had a borderline association: OR = 1.02 (95% CI: 1.00–1.03, p = .06).

Limitation:

The results are not generalizable to all cardiovascular surgical patients since only those undergoing invasive procedures were included in the study.

Conclusions:

Higher mean and maximum BG levels were associated with increased risk of in-hospital mortality but not with 30-day readmission. Further research is needed to identify optimal BG targets and the effects of avoiding extreme hyperglycemia on patient outcomes.

Key words::

• Blood glucose
• Cardiovascular
• Critical care
• Hyperglycemia
• Surgery

Transparency

Declaration of funding

Funding for this project was provided by Eli Lilly and Company (Indianapolis, IN, USA). Eli Lilly was involved in study conception and design, acquisition, analysis and interpretation of data, critical revision of the report, and the decision to submit the paper for publication. L.J.L. and M.E. participated in the generation of research question and hypothesis; L.J.L., M.E., S.A.M., D.F., J.B., H.-T.Y., T.H., and B.W.B. contributed to the study design; L.J.L., M.E., S.A.M., D.F., J.B., B.H.N., H.-T.Y., T.H., and B.W.B. participated in the analysis plan, interpretation of results, and the development, review and finalization of this manuscript.

Declaration of financial/other relationships

S.A.M., D.F., and J.B. are full-time employees and minor shareholders of Eli Lilly and Company. L.J.L. was a full-time employee of Eli Lilly and Company at the time of this study and is a minor shareholder. M.E., H.-T.Y., and T.H. are employees and stockholders of Cerner Corporation, which owns and licenses the HealthFacts database and performs consulting services for the pharmaceutical industry, including Eli Lilly and Company. B.H.N.’s company, OptiStatim LLC (Longmeadow, MA, USA), was paid a consultancy fee by Cerner Corporation and has no other conflicts of interest to report. B.W.B. is an endocrinologist at Atlanta Diabetes Associates; a paid consultant to this study; received research and grant support and participated in speaker’s bureaus for Eli Lilly and Company, Novo Nordisk, and Sanofi-Aventis; and is a stockholder and on the board of directors at GlucoTec.

CMRO peer reviewers may have received honoraria for their review work. The peer reviewers on this manuscript have disclosed that they have no relevant financial relationships.

Acknowledgements

The authors wish to thank Jarrett W. Coffindaffer PhD of i3, part of the inVentiv Health Company, for assistance in preparing the manuscript.