Abstract WP268: Associations Between Case Volume and Outcomes in the Subarachnoid Hemorrhage Patients With Clipping or Coiling: J-ASPECT Study

Abstract

Background: Many studies have reported that high-volume center was associated with the favorable outcomes in subarachnoid hemorrhage (SAH) patients with treatment. However, in Japan, the effect of the case volume of the hospital in SAH patients remains elusive. The aim of this study is to investigate the associations between case volume and outcomes of clipping or coiling using data obtained from the Japanese Diagnosis Procedure Combination [DPC]-based Payment System. Methods: Of the 847 certified training institutions of the Japan Neurosurgical Society, 327 institutions agreed to participate in this DPC discharge database study. Data on patients hospitalized for SAH between April 1, 2012 and March 31, 2013 were obtained from the DPC database. Patients hospitalized because of SAH were identified using International Classification of Diseases-10 diagnosis codes (I60.0-9). The case volumes of clipping and coiling in each hospital were divided into quintiles (Q1-Q4). Odd ratios (ORs) of in-hospital mortality and modified Rankin Scale (mRS) at discharge were estimated after adjustment for age, sex, comorbidities, and SAH severity. The category of Q1 was assigned a reference for OR. Results: A total of 5214 patients with SAH (3624 clipping, 1590 coiling) were analyzed. Mortality was 9.8%, and proportion of discharge mRS3-6 was 44.0%. No significant associations were found between case volume and in-hospital mortality in both the clipping (Q2, Q3, and Q4; OR = 0.97, 0.69, and 0.77; P = 0.902, 0.148, and 0.263) and coiling group (Q2, Q3, and Q4; OR = 0.94, 1.62, and 0.84; P = 0.864, 0.140, and 0.586). No significant associations were found between case volume and discharge mRS3-6 in both the clipping (Q2, Q3, and Q4; OR = 1.28, 1.27, and 1.09; P = 0.194, 0.189, and 0.619) and coiling group (Q2, Q3, and Q4; OR = 0.89, 1.15, and 0.78; P = 0.691, 0.599, and 0.315). Conclusion: In Japan, case volume did not show the correlation with outcomes in SAH patients. This nationwide database study reflects the real-world practice. <!--EndFragment-->