Retrospective analysis of the effects of steroid therapy and antidiabetic medication on survival in diabetic glioblastoma patients

AIMS: Type 2 diabetes mellitus (DM2) affects 10% of the population, but little is known about how DM2 and antidiabetic medication impact glioblastoma (GBM) patients.

PATIENTS & METHODS: We retrospectively reviewed GBM patients with DM2 seen at a single institution from 1998 to 2010.

RESULTS: Of 988 GBMs, 124 (12.6%) were affected by DM2. Thirty-four developed DM2 after steroid use and 89 had pre-existing DM2. Median overall survival among diabetic GBMs was 10 months compared with 13 months among nondiabetics. Only 15% of diabetic patients achieved sustained steroid taper. Sixty-seven (54%) were managed with a single antidiabetic medication and, within this monotherapy group, Karnofsky Performance Score, resection status, steroid dependency and metformin use were the most important predictors of survival on multivariate analysis.

CONCLUSION: The prevalence of DM2 among GBMs is similar to that of the general population. A more aggressive approach to steroid tapering and the choice of antidiabetic drug may improve survival within this patient population.