Propensity Score Matching Analysis for the Patients of Unruptured Cerebral Aneurysm from a Post Hoc Analysis of a Nationwide Database in Japan

Background: This study aimed to compare the functional outcome at discharge for unruptured cerebral aneurysms (UCAs) between surgical clipping and endovascular coiling in total, nonelderly (<65 years), and elderly (≥65 years) patients by nonbiased analysis based on a national database in Japan. Methods: A total of 15,671 patients with UCA were registered in the Diagnosis Procedure Combination, the nationwide database, from 2010 to 2015 in Japan. The outcome of the Barthel Index (BI) at discharge was investigated, and propensity score–matched analysis was conducted in total, nonelderly, and elderly patient groups. Results: Propensity score–matched analysis found no significant difference for in-hospital mortality between the 2 treatment methods in the total and both age-groups. The rate of morbidity of BI <90 at discharge was higher after surgical clipping than after endovascular coiling in the total (4.9% vs. 3.9%; P = 0.040; risk difference, –1.0%; 95% confidence interval, –3.6 to 2.3%) and the elderly age-group (8.1% vs. 5.0%; P < 0.001; risk difference, –3.1%; –4.8% to 1.5%), however, no significant association between the 2 treatment methods (2.4% vs. 2.6%; P = 0.67; risk difference, 0.22%; –0.79 to 1.22%) was found in the nonelderly group. Conclusions: In elderly patients with UCA, a better outcome at discharge after endovascular coiling was found. However, no significantly different functional outcome at discharge between surgical clipping and endovascular coiling for UCA in nonelderly patients was confirmed by propensity score–matched analysis from a nationwide database in Japan.