European Heart Journal Advance Access originally published online on July 16, 2009
European Heart Journal 2009 30(21):2584-2592; doi:10.1093/eurheartj/ehp288
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The relationship between body mass index, treatment, and mortality in patients with established coronary artery disease: a report from APPROACH
1 Department of Clinical Epidemiology, School of Public Health, University of Alberta, Edmonton, Alberta, Canada
2 Division of General Internal Medicine, University of Alberta, Edmonton, Alberta, Canada
3 Division of Nephrology and Hypertension, Harbor-UCLA Medical Center, Torrance, CA, USA
4 Division of Cardiology, University of Alberta, Edmonton, Alberta, Canada
5 Division of Endocrinology, University of Alberta, Edmonton, Alberta, Canada
6 Division of Nephrology, Salem Veterans Affairs Medical Center, Salem, VA, USA
7 Department of Medicine, University of Virginia, Charlottesville, VA, USA
8 Division of Cardiology, UCLA David Geffen School of Medicine, Los Angeles, CA, USA
9 School of Public Health, Faculty of Medicine and Nursing, University of Alberta, 4-140 F Clinical Sciences Building, 8440-112 Street, Edmonton, AB, Canada T6G 2B7
Received 25 June 2008; revised 19 May 2009; accepted 25 June 2009; online publish-ahead-of-print 16 July 2009.
* Corresponding author. Tel: +1 780 492 0644, Fax: +1 780 492 1219, Email: colleen.norris{at}ualberta.ca
Aims: Our objective was to examine the association between body mass index (BMI) and survival according to the type of treatment in individuals with established coronary artery disease (CAD).
Methods and results: Patients with CAD were identified in the Alberta Provincial Project for Outcome Assessment in Coronary Heart Disease (APPROACH) registry between January 2001 and March 2006. Analyses were conducted separately by treatment strategy [medical management only, percutaneous coronary intervention (PCI), or coronary artery bypass grafting (CABG)]. Patients were grouped according to six BMI categories. Multivariable-adjusted hazard ratios (HRs) for mortality were calculated using the Cox regression with the referent group for all analyses being normal BMI (18.5–24.9 kg/m2). The cohort included 31 021 patients with a median follow-up time of 46 months. In the medically managed only group, BMIs of 25.0–29.9 and 30.0–34.9 kg/m2 were associated with significantly lower mortality compared with normal BMI patients (adjusted HR 0.72; 95% CI 0.63–0.83 and adjusted HR 0.82; 95% CI 0.69.0–0.98, respectively). In the CABG group, BMI of 30.0–34.9 kg/m2 had the lowest risk of mortality (adjusted HR 0.75; 95% CI 0.61–0.94), whereas in the PCI group, BMI of 35.0–39.9 kg/m2 had the lowest risk of mortality (adjusted HR 0.65; 95% CI 0.47–0.90). Patients who were overweight or have mild or moderate obesity were also more likely to undergo revascularization procedures compared with those with normal BMI, despite having lower risk coronary anatomy.
Conclusion: A paradoxical association between BMI and survival exists in patients with established CAD irrespective of treatment strategy. Patients with obesity may be presenting earlier and receiving more aggressive treatment compared with those with normal BMI.
Key Words: Obesity • Coronary disease • Mortality • Epidemiology