title: Body mass index, cardiac surgery and clinical outcome. A single-center experience with 9125 patients.
abstract: OBJECTIVE
  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.
  
  
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Clinic for Thoracic and Cardiovascular Surgery, Heart Center NRW, Ruhr University Bochum, Bad Oeynhausen, Germany. Electronic address: azittermann@hdz-nrw.de.
authors.forename: A
authors.initials: A
authors.lastname: Zittermann
authors.affiliation: Clinic for Thoracic and Cardiovascular Surgery, Heart Center NRW, Ruhr University Bochum, Bad Oeynhausen, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Becker
authors.affiliation: Clinic for Thoracic and Cardiovascular Surgery, Heart Center NRW, Ruhr University Bochum, Bad Oeynhausen, Germany.
authors.forename: J F
authors.initials: JF
authors.lastname: Gummert
authors.affiliation: Clinic for Thoracic and Cardiovascular Surgery, Heart Center NRW, Ruhr University Bochum, Bad Oeynhausen, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Börgermann
mesh_terms: D000368:Aged; D015992:Body Mass Index; D006348:Cardiac Surgical Procedures / Q000401:mortality*; D023381:Endpoint Determination; D005260:Female; D005500:Follow-Up Studies; D017052:Hospital Mortality; D006801:Humans; D007362:Intensive Care Units; D007431:Intraoperative Complications / Q000209:etiology / Q000401:mortality*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications / Q000401:mortality; D050177:Overweight / Q000150:complications / Q000401:mortality; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D013851:Thinness / Q000150:complications / Q000401:mortality; D016896:Treatment Outcome
keywords: Body mass index; Cardiac surgery; Major adverse cardiac and cerebrovascular events; Mortality; Survival