Patterns and Outcomes of Intensive Care on Acute Ischemic Stroke Patients in the US

Background: Up to 20% of acute ischemic stroke (AIS) patients may benefit from intensive care unit (ICU)-level care; however, there are few studies evaluating ICU availability for AIS. We aim to summarize the proportion of elderly AIS patients in the United States who are admitted to an ICU and assess the national availability of ICU-level care in AIS. Methods: We performed a retrospective cohort study using de-identified Medicare inpatient datasets from January 1, 2016 through December 31, 2019 for US individuals aged ≥65 years. We used validated International Classification of Diseases, Tenth Revision, Clinical Modification codes to identify AIS admission and interventions. ICU-level care was identified by revenue center code. AIS patient characteristics and interventions were stratified by receipt of ICU-level care, comparing differences through calculated standardized mean difference score due to large sample sizes. Results: From 2016 through 2019, a total of 952 400 admissions by 850 055 individuals met criteria for hospital admission for AIS with 19.9% involving ICU-level care. Individuals were predominantly >75 years of age (58.5%) and identified as white (80.0%). Hospitals on average admitted 11.4% (SD 14.6) of AIS patients to the ICU, with the median hospital admitting 7.7% of AIS patients to the ICU. The ICU admissions were younger and more likely to receive reperfusion therapy but had more comorbid conditions and neurologic complications. Of the 5084 hospitals included, 1971 (38.8%) reported no ICU-level AIS care. Teaching hospitals (36.9% versus 1.6%, P<0.0001) with larger AIS volume (P<0.0001) or in larger metropolitan areas (P<0.0001) were more likely to have an ICU available. Conclusions: We found evidence of national variation in the availability of ICU-level care for AIS admissions. Since ICUs may provide comprehensive care for the most severe AIS patients, continued effort is needed to examine ICU accessibility and utility among AIS.