Long-term survival and residual hazard after in-hospital cardiac arrest

The purpose of this study was to determine long-term survival after in-hospital cardiac arrests and to explore if and when the excess mortality risk imposed by the index event reaches that of an age and sex matched general population.

A retrospective analysis of data from 1,571 in-hospital cardiac arrests between the calendar years 1997 and 2002 inclusive was performed. Two hundred and fifty-nine people survived until hospital discharge, 220 of which were residents in England and included in the study. Kaplan-Meier curves were constructed for the survivors and an age and sex matched comparator population, and survival compared with a one-sample log rank test. Smoothed hazard curves were constructed for the two populations. Differences in outcome from year of index event were also sought.

16.5% of patients survived to hospital discharge. Patients continue to experience a mortality rate greater than that of the comparator population during the first 200 days, with overall 70 deaths versus 18.7 as predicted from life tables (p < 0.0001). The hazard is greatest after resuscitation and falls thereafter until about 2 years where it is not very different to that of the comparator population and then subsequently rises. No evidence was found of a difference in the first year survival between patients resuscitated in different calendar years (p > 0.3 for all tests).

The residual risk to an individual cardiac arrest survivor's life is greatest during the first year of survival, but declines progressively during the first 2 years after the event, subsequently approaching the risk experienced by the general population.