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Body mass index, cardiac surgery and clinical outcome. A single-center experience with 9125 patients
A Zittermann1, T Becker1, J F Gummert1
1Clinic for Thoracic and Cardiovascular Surgery, Heart Center NRW, Ruhr University Bochum, Bad Oeynhausen, Germany.
Insights
Both underweight and severely obese patients face higher risks after cardiac surgery. Underweight individuals, in particular, show increased mid-term mortality and complications, requiring special attention.
Area of Science:
- Cardiology
- Surgical Outcomes
- Obesity Research
Background:
- A J-shaped association between Body Mass Index (BMI) and mortality exists in the general population.
- The impact of BMI on mortality and major adverse cardiac and cerebrovascular events (MACCE) in cardiac surgery patients remains unclear.
Purpose of the Study:
- To investigate the effect of BMI on MACCE, intensive care unit (ICU)-related outcomes, and mid-term mortality in cardiac surgical patients.
- To identify specific BMI categories associated with increased risks in this patient cohort.
Main Methods:
- Analysis of 9125 consecutive cardiac surgery patients operated on between July 2009 and July 2012.
- Categorization of patients into underweight, normal BMI, overweight, obese, and severely obese groups.
- Multivariable analysis to adjust for potential confounders and assess the association between BMI and outcomes.
Main Results:
- Severely obese patients had a higher odds ratio for MACCE (1.39) compared to overweight patients.
- Underweight and severely obese patients experienced longer mechanical ventilation and ICU stays.
- Underweight patients showed a significantly higher adjusted hazard ratio for 2-year mortality (1.72 vs. normal BMI, 2.07 vs. overweight BMI).
- Red blood cell concentrate requirements were highest in underweight patients.
Conclusions:
- Both severe obesity and underweight are independent risk factors for operative complications in cardiac surgery.
- Underweight status poses a significant risk for mid-term survival in patients undergoing cardiac surgery, warranting specific clinical attention.
Background And Aim:
There is evidence for a J-shaped association between Body Mass Index (BMI) and all-cause mortality in general populations. In cardiac surgical patients, the effect of BMI on mortality and major adverse cardiac and cerebrovascular events (MACCE) is not completely clear.
Methods And Results:
We investigated the effect of BMI on MACCE (primary endpoint), as well as intensive care unit (ICU)-related outcomes and mid-term mortality in 9125 consecutive patients who were operated on at our institution between July 2009 and July 2012. Of the study cohort, 3.0% were underweight (BMI < 20 kg/m(2)), 28.0% had a normal BMI (20-24.99 kg/m(2)), 43.1% were overweight (BMI 25-29.99 kg/m(2)), 19.3% were obese (BMI 30-34.99 kg/m(2)), and 6.6% were severely obese (BMI ≥ 35 kg/m(2)). Compared with overweight patients (lowest incidence of MACCE), the multivariable-adjusted odds ratio of MACCE in severely obese patients was 1.39 (95% CI: 1.03-1.87). Underweight and severely obese patients had the longest risk-adjusted duration of mechanical ventilator support and ICU stay (P-values 0.004-0.001). The red blood cell concentrates requirement was highest in underweight patients (P < 0.001). Compared with normal and overweight patients, the multivariable-adjusted hazard ratio of 2-year mortality was higher in underweight patients (1.72 [95% CI: 1.26-2.36] and =2.07 [95% CI: 1.51-2.83], respectively), but did not differ significantly in severely obese patients.
Conclusion:
Data demonstrate that both severe obesity and underweight are independent risk factors for operative complications in cardiac surgical patients. With respect to mid-term survival, special attention should be paid to underweight patients scheduled for cardiac surgery.
