Increased Long-Term Mortality in Type 2 Diabetics Undergoing Surgical Resection of a WHO Grade I Meningioma

Objectives: Previous authors have identified several factors that predict increased risk of long-term morbidity and mortality in patients undergoing resection of a meningioma. These factors include patient age, pathological grade, tumor location, and extent of resection. Additionally, type 2 Diabetes Mellitus (DM) has been increasingly associated with poor long-term outcomes in several patient populations undergoing surgical resection of various tumors. As such, we sought to study the role of Type 2 DM in predicting the long-term survival of patients undergoing surgical resection of a WHO Grade I meningioma.

Methods: We conducted a retrospective cohort study on 196 patients who had a WHO Grade I meningioma resected at our institution between 2001–2013. The medical record was reviewed to identify a pre-existing diagnosis of type 2 DM and to obtain patient age, gender, body mass index (BMI), perioperative blood glucose levels, extent of surgical resection, tumor pathological grade, details of any radiation therapy, and Karnofsky Performance Status (KPS) scores. Patient mortality was reviewed by medical record and Social Security Death Index (SSDI). Variables associated with survival in a univariate analysis were included in the multivariate Cox model if p < 0.10. Variables with probability values >0.05 were then removed from the multivariate model in a step-wise fashion.

Results: 196 patients met the inclusion criteria and were included in the study. 33 (17%) patients had pre-existing diagnoses of type II DM prior to clinical presentation. As of last chart review, the rate of eventual mortality was 24.2% amongst diabetics versus 7.4% in non-diabetics. Mean survival time in diabetic patients was 52.1 months compared with 160.9 months in non-diabetics. The decreased survival rate and time in patients with type 2 DM were found to be statistically significant (p = 0.008 and p < 0.0001, respectively). In a multivariate Cox analysis, a pre-existing history of type II DM was independently associated with decreased survival following the resection of a WHO Grade I meningioma (OR=-2.6, p = 0.045).

Conclusions: A pre-existing diagnosis of type 2 DM predicts relatively poor long-term survival following the resection of a WHO Grade I meningioma. This relationship is independent of previously identified prognostic indicators following meningioma resection. Our data reaffirms that in patients with resected benign meningiomas, the extent of pre-existing medical comorbidity (in this case type II DM) is a strong predictor of long-term outcomes. Further studies are needed to better identify the efficacy of aggressive glycemic control and medical optimization in reducing the markedly increased risk of mortality in diabetic patients after the resection of a WHO Grade I meningioma.