Correlations Between Physician and Hospital Stroke Thrombectomy Volumes and Outcomes: A Nationwide Analysis.

Abstract

Despite the Joint Commission’s certification requirement of ≥15 stroke thrombectomy (ST) cases per center and proceduralist annually, the relationship between ST case volumes and outcomes is uncertain. We sought to determine whether a proceduralist or hospital volume threshold exists that is associated with better outcomes among Medicare beneficiaries. Retrospective cohort study using validated International Classification of Diseases, Tenth Revision, Clinical Modification codes to identify admissions with acute ischemic stroke and treatment with ST. We used de-identified, national 100% inpatient Medicare data sets from January 1, 2016, to December 31, 2017 for US individuals aged ≥65 years. We calculated total procedures by proceduralist and hospital. We performed adjusted logistic regression of total cases as a predictor of inpatient mortality, good outcome (defined by dichotomized discharge disposition of inpatient rehabilitation or better), and 30-day readmission. We adjusted for sex, age, Charlson Comorbidity Index, availability of neurocritical care, teaching hospital status, socioeconomic status, 2-year stroke volume, and urban versus rural hospital location. We dichotomized case numbers incrementally to determine a volume threshold for better outcomes. Thirteen thousand three hundred thirty-five patients were treated with ST by 2754 proceduralists at 641 hospitals. For every 10 more proceduralist cases, patients had 4% lower adjusted odds of inpatient mortality (adjusted odds ratio, 0.96 [95% CI, 0.95–0.98], P<0.0001) and 3% greater adjusted odds of good outcome (adjusted odds ratio, 1.03 [95% CI, 1.02–1.04], P<0.0001). For every 10 more hospital cases, patients had 2% lower odds of inpatient mortality (adjusted odds ratio, 0.98 [95% CI, 0.98–0.99], P=0.0003) and 2% greater odds of good outcome (adjusted odds ratio, 1.02 [95% CI, 1.01–1.02], P<0.0001). With increasing volumes, there were higher odds of better outcomes. Nationally, higher proceduralist and hospital ST case volumes were associated with reduced inpatient mortality and better outcome. These data support volume requirements in guidelines for ST training and certification.