Survival from Non‐Traumatic Out‐of‐Hospital Cardiac Arrest Is Worse on Weekends Compared with Weekdays: A Report from the 2010 Nationwide Inpatient Sample

Background:

In the United States, survival in patients experiencing out‐of‐hospital cardiac arrest varies significantly between and within hospitals. Many studies have shown less favorable outcomes for cardiovascular disease entities on weekends relative to weekdays. We investigated whether outcomes are similarly affected in patients with non‐traumatic out‐of‐hospital cardiac arrest (OHCA).

Methods:

The 2010 Nationwide Inpatient Sample and Nationwide Emergency Department Sample are nationally representative databases containing data on 8 and 21 million discharges, respectively. We included all patients with an ICD‐9 CM code for a principle diagnosis of cardiac arrest and excluded those with ICD‐9 CM code for any diagnosis of trauma. We defined “weekend” as Saturday 12:01 am to Sunday 11:59 pm. The primary outcome was a composite endpoint of in‐hospital death or discharge to hospice. Secondary outcomes included use of therapeutic hypothermia, rate of in‐hospital re‐arrest, coronary artery stenting, device implantation and neurologic outcome on discharge. Poor neurologic outcome was defined as the composite endpoint of coma, vegetative state or anoxic brain injury with feeding tube or tracheostomy placement in patients discharged alive. Comorbidity was assessed using the Charlson Comorbidity Index (CCI). Adjusted odds ratios were calculated using multivariable regression analyses

Results:

In 2010, 140,128 OHCA patients were admitted to an ED in the United States; 29.3% occurred on the weekend. Ventricular fibrillation was the presenting rhythm in 3.8% of emergency department OHCA visits. Characteristics of patients surviving to hospital admission on weekends were not significantly different from those surviving to admission on weekdays except for female gender (43.5% vs. 40.4%, p=0.004) and CCI=1 (31.2% vs. 29.3%, p=0.032). Overall survival to hospital admission and discharge were only 8.2% and 3.6% respectively. When adjusted for age, gender, race, comorbidities, and hospital location, region, size and teaching status, total in‐hospital mortality remained higher on weekends compared with weekdays (adjusted OR 1.25; 95% CI: 1.01 to 1.55). All secondary outcomes were similar between weekend and weekday arrests.

Conclusions:

Survival to discharge from non‐traumatic out‐of‐hospital cardiac arrest was lower if arrests occurred on weekends compared to weekdays, even when accounting for common patient and hospital characteristics. Further investigations are warranted to explain this nationwide observation.