Cardiac Arrest Survival Highest at Hospitals With Fewest

Jenni Laidman

May 20, 2013

Hospitals with the highest survival rates for in-hospital cardiac arrest also appear to be better at preventing cardiac arrests in the first place, according to a study published online May 20 in JAMA Internal Medicine.

Lena M. Chen, MD, clinical lecturer, Division of General Medicine, University of Michigan, Ann Arbor, and colleagues reviewed 102,153 cases of in-hospital cardiac arrest among patients aged 18 years and older in 358 hospitals from January 1, 2000, to November 30, 2009. The data came from Get With the Guidelines–Resuscitation, formerly the National Registry of Cardiopulmonary Resuscitation, a prospective national registry of in-hospital cardiac arrests. The current analysis was restricted to hospitals with 50 or more arrests during the study period.

The analysis showed less than 20% of patients with in-hospital cardiac arrests survived to discharge, with a median hospital case-survival rate of 18.8% (interquartile range [IQR], 14.5% - 22.6%; range, 2.5% - 46.9%). The median hospital incidence rate was 4.02 arrests per 1000 admissions (IQR, 2.95 - 5.65 per 1000 admissions; range, 0.90 - 18.4 per 1000 admissions).

A crude analysis showed hospitals with the highest case-survival rates had lower arrest incidence (r, −0.16; P = .003). The relationship remained relatively unchanged (r, −0.15; P = .004) when adjusted for patient case mix.

When investigators adjusted for hospital characteristics, they found an attenuated relationship between incidence and case survival (r, −0.07; P = .18).

"This finding suggests that the correlation between cardiac arrest incidence and case survival was partly attributable to the hospital factors in the model," the authors write. A hospital's nurse-to-bed ratio and geographic region correlated with the greatest shift in the relationship between incidence and survival.

The researchers adjusted for other hospital characteristics as well, including the hospital's teaching status (major, minor, nonteaching), ownership (nonprofit, public, private), location (urban vs rural), certification status as a trauma center, bed number, and case-mix index.

Previous studies have focused on factors associated with improved in-hospital survival while neglecting to note the incidence rate.

"Hospitals that excelled at preventing cardiac arrests also had higher survival rates for cardiac arrest cases, and this correlation persisted after adjustment for patient case mix," the authors write.

The authors report that study limitations include the possibility of some unmeasured confounding factor. In addition, the study was restricted to hospitals participating in the Get With the Guidelines–Resuscitation and may not be generalizable across hospitals. Only a handful of hospital factors were examined, and there was no specific information on nurse and physician experience and training, nor was there information on quality improvement resuscitation programs, the authors note.

The investigators did not include cardiac arrests for patients with do-not-resuscitate orders in the number of patients who survived a cardiac arrest. However, incomplete data made it impossible to exclude all patients with DNR orders from the total number of cardiac arrests, so the correlation between unadjusted incidence and case survival may be an overestimate, the authors write.

The authors have disclosed no relevant financial relationships.

JAMA Intern Med. Published online May 20, 2013. Abstract


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