Clinical Factors Associated With Survival in In-Hospital Cardiac Arrest

Despite advancements in resuscitation guidelines, in-hospital cardiac arrests (IHCA) remain associated with high mortality and morbidity. We aimed to evaluate predictive factors associated with survival in patients suffering an IHCA. A systematic literature search was conducted to identify studies reporting factors associated with survival to hospital discharge following IHCA (2000-2024; English language). Data were extracted for all reported variables including patient demographics, arrest characteristics, and interventions. Variables with low heterogeneity were meta-analyzed using a random-effects model to generate odds ratios (OR) or standardized mean differences (SMD) for survival. Twelve studies comprising 5,088 patients were included. Key predictors of survival included witnessed arrest (OR 2.99, p=0.009), arrest in the operating room (OR 2.19, p=0.005), initial shockable rhythm (OR 3.96, p<0.001), and cardiac cause for arrest (OR 3.44, p<0.001). Conversely pulseless electrical activity as the initial rhythm (OR 0.47, p<0.001) and older age (SMD -0.30, p=0.03) were associated with increased mortality. Sex, baseline comorbidities, CPR duration, and requirement of extracorporeal membrane oxygenation were not significant, and high heterogeneity was observed for CPR (I²=97%), witnessed arrest (I²=89%), and shockable rhythm (I²=83%), which should be considered when interpreting the pooled estimates. In conclusion, survival following IHCA is more strongly associated with arrest characteristics and clinical context than baseline comorbidity burden. These findings may support early risk stratification and guide peri-arrest decision-making. STUDY REGISTRATION: PROSPERO CRD42024520780 CLINICAL PERSPECTIVES: In-hospital cardiac arrest (IHCA) carries persistently high mortality despite advances in resuscitation. This meta-analysis of 12 studies comprising 5,088 patients demonstrates that survival is predominantly determined by arrest-specific and contextual factors rather than baseline comorbidity burden. Shockable initial rhythm, witnessed arrest, cardiac etiology, and procedural arrest location were the strongest predictors of survival, while non-shockable rhythms, intubation and older age predicted mortality. Sex and traditional cardiovascular risk factors were not significantly associated with outcomes. These findings support early peri-arrest risk stratification, resuscitation decisions and inform goals-of-care discussions in patients experiencing IHCA.