Association between hospital ownership and patient selection, management, and outcomes after carotid endarterectomy or carotid artery stenting: – Secondary data analysis of the Bavarian statutory quality assurance database –

Background: This study analyses the association between hospital ownership and patient selection, treatment, and outcome of carotid endarterectomy (CEA) or carotid artery stenting (CAS). Methods: The analysis is based on the Bavarian subset of the nationwide German statutory quality assurance database. All patients receiving CEA or CAS for carotid artery stenosis between 2014 and 2018 were included. Hospitals were subdivided into four groups: university hospitals, public hospitals, hospitals owned by charitable organizations, and private hospitals. The primary outcome was any stroke or death until discharge from hospital. Research was funded by Germany’s Federal Joint Committee Innovation Fund (01VSF19016 ISAR-IQ). Results: In total, 22,446 patients were included. The majority of patients were treated in public hospitals (62%), followed by private hospitals (17%), university hospitals (16%), and hospitals under charitable ownership (6%). Two thirds of patients were male (68%), and the median age was 72 years. CAS was most often applied in university hospitals (25%) and most rarely used in private hospitals (9%). Compared to university hospitals, patients in private hospitals were more likely asymptomatic (65% vs. 49%). In asymptomatic patients, the risk of stroke or death was 1.3% in university hospitals, 1.5% in public hospitals, 1.0% in hospitals of charitable owners, and 1.2% in private hospitals. In symptomatic patients, these figures were 3.0%, 2.5%, 3.4%, and 1.2% respectively. Univariate analysis revealed no statistically significant differences between hospital groups. In the multivariable analysis, compared to university hospitals, the odds ratio of stroke or death in asymptomatic patients treated by CEA was significantly lower in charitable hospitals (OR 0.19 [95%-CI 0.07–0.56, p = 0.002]) and private hospitals (OR 0.47 [95%-CI 0.23–0.98, p = 0.043]). In symptomatic patients (elective treatment, CEA), patients treated in private or public hospitals showed a significantly lower odds ratio compared to university hospitals (0.36 [95%-CI 0.17–0.72, p = 0.004] and 0.65 [95%-CI 0.42-1.00, p = 0.048], respectively). Conclusions: Hospital ownership was related to patient selection and treatment, but not generally to outcomes. The lower risk of stroke or death in the subgroup of electively treated patients in private hospitals might be due to the right timing, the choice of treatment modality or actually to better structural and process quality.