Adverse events in brain tumor surgery: incidence, type, and impact on current quality metrics.

We found that most predictors of outcome rates are based on preoperative underlying medical conditions and are not modifiable by the surgeon. Comparing our results to the literature, we conclude that differences in readmission and reoperation rates are strongly influenced by standards in decision making and that comparison of outcome rates between different health-care providers on an international basis is challenging. Each health-care system has to develop own metrics for risk adjustment that require regular reassessment.