Association of preoperative glucose concentration with mortality in patients undergoing craniotomy for brain tumor

OBJECTIVE Hyperglycemia is associated with worse outcomes in ambulatory settings and specialized hospital settings, but there are sparse data on the importance of preoperative blood glucose measurement before brain tumor craniotomy. The authors sought to investigate the association between preoperative glucose level and 30-day mortality rate in patients undergoing brain tumor resection. METHODS This retrospective cohort study included patients undergoing craniotomy for brain tumors at West China Hospital, Sichuan University, from January 2011 to March 2021. Surgical mortality rates were evaluated in patients who had normal glycemia (< 5.6 mmol/L) as well as mild (5.6–6.9 mmol/L), moderate (7.0–11.0 mmol/L), and severe hyperglycemia (> 11.0 mmol/L). RESULTS The study included 12,281 patients who underwent tumor resection via craniotomy. The overall 30-day mortality rate was 2.0% (242/12,281), whereas the rates for normal glycemia and mild, moderate, and severe hyperglycemia were 1.5%, 2.5%, 3.8%, and 6.5%, respectively. Compared with normal glycemia, the odds of mortality at 30 days were higher in patients with mild hyperglycemia (adjusted odds ratio [OR] 1.44, 95% confidence interval [CI] 1.05–2.00), moderate hyperglycemia (OR 2.04, 95% CI 1.41–2.96), and severe hyperglycemia (OR 3.76, 95% CI 1.96–7.20; p < 0.001 for trend). When blood glucose was analyzed as a continuous variable, for each 1 mmol/L increase in blood glucose, the adjusted OR of 30-day mortality was 1.13 (95% CI 1.08–1.19). The addition of a preoperative glucose level significantly improved the area under the curve and categorical net reclassification index for prediction of mortality. CONCLUSIONS In patients undergoing craniotomy for brain tumors, even mild hyperglycemia was associated with an increased mortality rate, at a glucose level that was much lower than the commonly applied level.