The study ‘Cerebral aneurysms: Germany-wide real-world outcome data of endovascular or neurosurgical treatment from 2007 to 2019’1 is a clear example of administrative database misuse. Since administrative and claims databases are intended for billing purposes, they contain sparse information about the pathology treated. This fact largely disqualifies them as clinical resources for studies comparing two treatment modalities, particularly for pathologies such as cerebral aneurysms with many nuances that influence treatment decisions.

Administrative databases are adequate for comparing specific and relatively homogeneous elements within pathologies or treatment modalities over time, such as observing broad trends. These types of data are meant for billing and reimbursement, and not clinical studies. Studies using these databases for clinical outcomes must be very narrow in scope to overcome this limitation.

In this study, missing information includes aneurysm …