Volume-outcome trends in ruptured intracranial aneurysm treatment: German healthcare data from 2013 to 2022.

BACKGROUND

Subarachnoid hemorrhage (SAH) is a life-threatening condition with a high risk of disability requiring specialized care. This study investigated the relationship between hospital annual case volume and outcomes for patients undergoing clipping and endovascular treatment (EVT) of ruptured intracranial aneurysms (IAs) in Germany.

METHODS

German Federal Statistical Office data (2013-2022) derived from all German hospitals were analyzed for ruptured IA cases treated with EVT or clipping. Primary outcomes were in-hospital mortality and poor neurological outcome according to the National Inpatient Sample-SAH Outcome Measure. Poisson regression was used to assess the annual case volume-outcome relationship.

RESULTS

In 35 187 treatment cases for ruptured IA, a significant inverse relationship was found between annual case volume and both mortality and poor neurological outcomes for both treatment modalities. Each additional case performed annually decreased adverse outcome risk by 1%. EVT showed lower rates of poor neurological outcome (39.8% vs 49.8%, P<0.001), shorter hospital stays, less intensive care, and lower costs, but similar in-hospital mortality rates (18.5% vs 19.1%, P=0.127) compared with clipping. The in-hospital mortality rate for clipping increased in 2016-2018, 2021, and 2022 compared with the 2013 baseline, whereas it remained stable for EVT. Age was a significant predictor of mortality and poor neurological outcome.

CONCLUSIONS

This study is the first to quantify the volume-outcome relationship for treatment of ruptured IAs in Germany. Consistent results across treatment modalities suggest benefits of increased experience of neurovascular treatment centers. These findings enhance our understanding of factors influencing neurovascular care outcomes in Germany.