Frequency of Intubation for Medicare Beneficiaries With Acute Stroke and Association With Patient Outcomes

Intubation for acute stroke is common in the United States, with few established guidelines.

This is a retrospective observational study of acute stroke admissions from 2011 to 2018 among fee-for-service Medicare beneficiaries aged 65-100 years. Patient demographics and chronic conditions as well as hospital characteristics were identified. We identified patient intubation, stroke subtype (ischemic vs intracerebral hemorrhage), and thrombectomy. Factors associated with intubation were identified by a linear probability model with intubation as the outcome and patient characteristics, stroke subtype, and thrombectomy as predictors, adjusting for within-hospital correlation. We compared hospital characteristics between adjusted intubation rate quartiles. We specified a linear probability model with 30-day mortality as the patient-level outcome and hospital intubation rate quartile as the categorical predictor, again adjusting for patient characteristics. We specified an analogous model for quartiles of hospital referral regions.

There were 800,467 stroke hospitalizations at 3,581 hospitals. Among 2,588 hospitals with 25 or more stroke hospitalizations, the median intubation rate was 4.8%, while a quarter had intubation rates below 2.4% and 10% had rates above 12.5%. Ischemic strokes had a 21% lower adjusted intubation risk than intracerebral hemorrhages (risk difference [RD] -21.1%, 95% CI -21.3% to -20.9%; p < 0.001), whereas thrombectomy was associated with a 19.2% higher adjusted risk (95% CI RD 18.8%-19.6%; p < 0.001). Women and older patients had lower intubation rates. Large, urban hospitals and academic medical centers were overrepresented in the top quartile of hospital adjusted intubation rates. Even after adjusting for available characteristics, intubated patients had a 44% higher mortality risk than non-intubated patients (p < 0.001). Hospitals in the highest intubation quartile had higher adjusted 30-day mortality (19.3%) than hospitals in the lowest quartile (16.7%), a finding that was similar when restricting to major teaching hospitals (22.3% vs 18.1% in the 4th vs 1st quartiles, respectively). There was no association between market quartile of intubation and patient 30-day mortality.

Intubation for acute stroke varied by patient and hospital characteristics. Hospitals with higher adjusted rates of intubation had higher patient-level 30-day mortality, but much of the difference may be due to unmeasured patient severity given that no such association was observed for health care markets.