Background
In-hospital cardiac arrest is a major adverse event of hospitalization, with an incidence of 1-6/1000 admissions. 
It has been poorly researched and data on survival is limited. The outcome of interest in cardiac arrest research is predominantly survival to discharge, however recent guidelines warrant for more long-term outcomes. This systematic review aims to quantitatively summarize one-year survival after in-hospital cardiac arrest.
Methods
For this systematic review and meta-analysis we performed a systematic search of all published data on one-year survival after IHCA up to March 9th, 2018.  Our searches yielded 5984 results of which 37 were used. Results of the meta-analyses are presented as pooled proportions with corresponding 95% confidence intervals (CI). Between-study heterogeneity was assessed using I2 statistic and the DerSimonian-Laird estimator for τ2. Subgroup analyses were performed for cardiac and non-cardiac patients and a post-hoc analysis for good cognitive performance (CPC1-2).
Results
We included 40 studies in our systematic review and meta-analysis. The pooled one-year survival after in-hospital cardiac arrest was 13.0% (11.0% - 15.0%; I2=99.7%). Subgroup analysis of cardiac patients revealed a one-year survival of 40% (95% CI: 32% - 48%), in patients with a non-cardiac admission characteristic one-year survival was 10% (95% CI: 9% - 12%).  These data cover the period 1985 – 2018 and show no significant change in survival over that period. Cognitive performance was CPC1-2 in 92% (95% CI: 85%- 96%) 
of one-year survivors.
Interpretation
One-year survival after in-hospital cardiac arrest is poor. Survival is higher in patients admitted to cardiac wards. The time trend between 1985-2018 has shown no significant improvement in one-year survival rates. Research into IHCA population characteristics might elicit the issue of stagnated survival over the past decades. 


06 / One-year survival after in­­­­­-hospital cardiac arrest: a systematic review and meta-analysis

06 / One-year survival after in-hospital cardiac arrest: a systematic review and meta-analysis