Overweight, Obese Patients Show Better Survival After Shockable In-Hospital Cardiac Arrest Events: Study
USA: A recent study published in the Resuscitation journal sheds light on the complex relationship between body mass index (BMI) and survival outcomes in patients experiencing in-hospital cardiac arrest (IHCA). Conducted by Dr. Nobuhiro Ikemura and colleagues from the UMKC Healthcare Institute for Innovations in Quality, Kansas City, the study analyzed data from over 56,000 patients to understand how BMI influences both survival to discharge and neurologically favorable outcomes.
"The study of 56,411 in-hospital cardiac arrest patients found that underweight individuals (BMI <18.5 kg/m²) had significantly lower odds of favorable neurological survival (OR 0.64) and survival to discharge (OR 0.76), regardless of rhythm type," the researchers reported. "In contrast, overweight and obese patients showed improved outcomes (OR ~1.17), but only in cases with shockable rhythms. No survival benefit was observed for individuals with very high obesity levels."
Using data collected from the Get With The Guidelines-Resuscitation registry between 2006 and 2012, the researchers categorized patients based on BMI: underweight (<18.5 kg/m²), normal (18.5–24.9), overweight (25.0–29.9), obese (30.0–34.9), and very obese (≥35.0). Two key outcomes were assessed: survival to hospital discharge and favorable neurological status at discharge, defined as a cerebral performance category (CPC) score of 1.
The key findings were as follows:
- Among 10,219 patients with shockable cardiac rhythms, 29.4% achieved favorable neurological survival.
- In the same group, 38.7% survived to hospital discharge.
- Overweight patients with shockable rhythms had a 17% higher likelihood (OR 1.17) of favorable neurological outcomes compared to those with normal BMI.
- Obese patients with shockable rhythms had a 16% higher likelihood (OR 1.16) of favorable neurological outcomes.
- Underweight patients with shockable rhythms had significantly lower odds (OR 0.64) of favorable neurological survival.
- Among 46,192 patients with non-shockable cardiac rhythms, survival advantages were not seen in overweight or obese individuals.
- In the non-shockable rhythm group, underweight patients had poorer neurological outcomes (OR 0.76).
- Underweight patients with non-shockable rhythms also had lower overall survival to discharge (OR 0.85).
- There were no significant outcome differences in other BMI categories among patients with non-shockable rhythms.
The findings highlight that BMI plays a varying role depending on the type of cardiac arrest rhythm. While being overweight or obese may offer a protective advantage in cases of shockable rhythms, this benefit does not extend to non-shockable events. Regardless of rhythm type, underweight individuals consistently had the poorest outcomes.
The authors caution that these results should be interpreted in the context of certain limitations. The registry discontinued the collection of height and weight data after 2012, which may limit the applicability of findings to current resuscitation practices, especially given evolving treatment guidelines.
"Despite this, the study provides valuable insights into how body composition may influence cardiac arrest outcomes and highlights the need for tailored clinical strategies that consider BMI as a potential prognostic factor. Further research is needed to explore the underlying mechanisms and to evaluate whether weight-related interventions could impact post-arrest survival and recovery," the authors concluded.
Reference:
Ikemura, N., Spertus, J. A., Cho, Y. J., Jones, P. G., Jawad, M. A., O’Keefe, E. L., & Chan, P. S. (2025). Association Between Body Mass Index and Survival Outcomes for In-Hospital Cardiac Arrest. Resuscitation, 110671. https://doi.org/10.1016/j.resuscitation.2025.110671
