Effect of body mass index on survival after sudden cardiac arrest

Abstract

Background Although elevated body mass index (BMI) is a risk factor for cardiac disease, patients with elevated BMI have better survival in the context of severe illness, a phenomenon termed the “obesity paradox.” Hypothesis Higher BMI is associated with lower mortality in sudden cardiac arrest (SCA) survivors. Methods Data were collected on 1433 post‐SCA patients, discharged alive from the hospitals of the University of Pittsburgh Medical Center between 2002 and 2012. Of those, 1298 patients with documented BMI during the index hospitalization and follow‐up data constituted the study cohort. Results In the overall cohort, 30 patients were underweight (BMI <18.5 kg/m2), 312 had normal weight (BMI 18.5–24.9 kg/m2), 417 were overweight (BMI 25.0–29.9 kg/m2), and 539 were obese (BMI ≥30 kg/m2). As expected, the prevalence of coronary artery disease, myocardial infarction, diabetes mellitus, and hypertension increased significantly with increasing BMI. Over a median follow‐up of 3.6 years, 602 (46%) patients died. Despite higher prevalence of cardiovascular comorbidities in more obese patients, a higher BMI was associated with lower all‐cause mortality on univariate analysis (hazard ratio: 0.86 per increase by 1 BMI category, 95% confidence interval: 0.78‐0.94, P = 0.002) and multivariate analysis after adjusting for unbalanced baseline comorbidities (hazard ratio: 0.86 per increase by 1 BMI category, 95% confidence interval: 0.77‐0.96, P = 0.009). Conclusions Higher BMI is associated with lower all‐cause mortality in survivors of SCA, suggesting that the obesity paradox applies to the post‐arrest population. Further investigation into its mechanisms may inform the management of post‐SCA patients.

Leptin as a Key between Obesity and Cardiovascular Disease

“… 23 Similar results were observed in patients who experienced sudden cardiac arrest, wherein a higher BMI was associated with reduced mortality. 24 Higher BMI was also associated with lower mortality in cases of coronary artery disease, heart failure, and diabetes. 25 In general, obese patients have higher mortality; however, paradoxically, higher mortality is often observed in normal-weight patients compared with obese patients.…”

Does Obesity Influence the Outcome of the Patients Following a Cardiac Arrest?

“…Saba et al showed that higher BMI is associated with lower all-cause mortality in the survivor of sudden cardiac arrest, suggesting the obesity paradox also applies to the post-cardiac arrest population. 6 In contrast, a single-center trial by Breathett et al demonstrated BMI <30 compared with BMI ≥30 was associated with better survival post-hypothermia for cardiac arrest. 9 …”

“…There is an impression that obesity confers some survival advantages in heart failure and cardiac surgery. 4 – 6 , 12 This inverse correlation between BMI and mortality is known as the obesity paradox. Greater metabolic reserve, younger age, and better cardioprotective medical therapy to obese patients are some hypotheses postulated for this phenomenon.…”

“…Studies examining obese patients who suffered cardiac arrest provided conflicting results. 6 – 10 The American Heart Association National Registry of Cardiopulmonary Resuscitation (NRCPR) demonstrated a higher rate of survival to discharge for overweight and obese patients compared with underweight and normal-weight patients with cardiac arrest caused by shockable rhythms. 8 In contrast, body mass index (BMI) was not associated with in-hospital mortality in those who underwent extracorporeal cardiopulmonary resuscitation (ECPR).…”

Non-Coding RNAs to Aid in Neurological Prognosis after Cardiac Arrest

“…In a large registry, men had a higher survival rate and a better neurological outcome at hospital discharge than women [13]. As for other cardiovascular diseases, survival expectancy after CA might be higher in obese patients and smokers (often called obesity and smoking paradoxes) [14,15,16], even though these are known risk factors triggering this cardiovascular complication. The delay between cardiac arrest and return of spontaneous circulation (ROSC), as well as the subsequent extent of brain damage, are both strongly associated with a poor outcome [17].…”