Patients with Out-Of-Hospital Cardiac Arrest Treated at Teaching Hospitals Are More Likely to Survive to 30 Days, Compared with Non-Teaching Hospitals

In a large population-based study, a significant and sustained survival benefit was observed in patients with out-of-hospital cardiac arrest treated at teaching hospitals. The report of the study led by Dr. Czarnecki was recently published in Circulation: Cardiovascular Quality and Outcomes.

In Canada, teaching hospitals are university-affiliated centers with accredited residency programs that act as referral centers. They typically have advanced cardiac centers for myocardial infarction treatment. In the United States, the teaching status of the hospital is associated with lower mortality in a variety of conditions. Still, this association is not evaluated in patients presenting after out-of-hospital cardiac arrest (OHCA). Dr. Czarnecki and his collogues aimed to investigate the impact of the teaching status of the hospital on the 30-day survival of the patients with OHCA.

In a retrospective observational cohort study, the investigators pulled data from several population-based databases in Ontario, Canada. A total of 25,346 Patients older than 20 years who arrived alive to the hospital after OHCA between April 2017 and March 2014 were included in the study. Of those, 5,413 were treated at teaching and 19,933 at non-teaching hospitals. Cardiac catheterization, percutaneous coronary intervention, and specialist consultations were performed more frequently in teaching hospitals.  The median time to cardiac catheterization was one day at teaching hospitals, compared to 4 days at non-teaching hospitals.

There was a significant difference in survival early after initial presentation, evident as survival to intensive care unit admission (36.7% in teaching vs. 28.2% in non-teaching hospitals (P<0.001). The difference in survival was still significant after 3 days (21.2% at teaching vs. 16.4% in non-teaching hospitals ((P<0.001). The 30-day survival was also significantly higher in the teaching hospitals (13.9% vs. 11.0% in non-teaching hospitals, P<0.001). After adjusting for baseline characteristics, hospital teaching status was associated with a significantly higher adjusted odds of 30-day survival (OR, 1.38 [95% CI, 1.14–1.67]). This improved survival was more pronounced in patients younger patients (≤65 years: OR, 1.41 [95% CI, 1.14–1.74]; 66 to 80 years: OR, 1.37 [95% CI, 1.13–1.67]). The teaching status of the hospital was not associated with survival in patients older than 80 (OR, 1.07 [95% CI, 0.79–1.44]).

Several caveats should be considered when interpreting the results. There was no data regarding arrest characteristics such as presenting rhythm, duration of the arrest, whether bystander cardio-pulmonary resuscitation was performed, or transport time to the hospital. There process of care in the ED is not available in both groups. The main outcomes of the study were 3-day and 30-day survival. Non-mortality-related quality measures such as functional status and neurologic outcome of the survivors are not reported. Also, the patients presented to the non-teaching hospital were more rural residents. Although the analyses have been adjusted for it, it might be still a source of bias.