Chronological and Biological Age in Predicting Outcomes of Older Patients in Neurosurgery

Although chronological age is an important factor in indications and predicting outcomes of neurosurgery, it is essential to consider biological age, particularly in older patients, due to individual differences such as frailty. The simplified 5-factor modified frailty index has recently been introduced. This study investigated its role in predicting the outcomes of meningioma and unruptured cerebral aneurysm surgery by analyzing data from the Diagnosis Procedure Combination database in Japan from 2010 to 2014. Although the 5-factor modified frailty index scores could predict the risk of in-hospital worsening outcomes, mortality, and complications in meningioma surgery, it was more useful in non-elderly patients aged <65 years rather than in elderly patients aged ≥75 years. Additionally, in patients aged <74 years, in-hospital complications of unruptured cerebral aneurysms were more associated with the 5-factor modified frailty index than with chronological age.Alternatively, in patients with aneurysmal subarachnoid hemorrhage, previous reports have suggested a non-linear correlation between age and the outcome, but no reports have explored this relationship. Therefore, we visualized a clear non-linear correlation between age and poor outcomes, which can aid clinical decision-making and better inform and guide patients with aneurysmal subarachnoid hemorrhage and their families. We could validate this visualization using a separate cohort based on the discrimination property and calibration plot. Progress has been made in predicting outcomes for older patients undergoing neurosurgery in Japan; however, in the future, more individualized and specific predictions will be required.