European Heart Journal Advance Access originally published online on February 12, 2008
European Heart Journal 2008 29(5):594-601; doi:10.1093/eurheartj/ehn010
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Impact of obesity as a mortality predictor in high-risk patients with myocardial infarction or chronic heart failure: a pooled analysis of five registries
1 Division of Cardiology, Department of Medicine, Glostrup University Hospital, Nrd Ringvej, Glostrup 2600, Denmark
2 Division of Cardiology, Department of Medicine, Rigshospitalet Heart Centre, Copenhagen, Denmark
3 Department of Cardiology, Gentofte University Hospital, Copenhagen, Denmark
4 Clinic of Internal Medicine I, Bispebjerg University Hospital, Copenhagen, Denmark
5 London School of Hygiene and Tropical Medicine, London, UK
6 Department of Cardiology, Bispebjerg University Hospital, Copenhagen, Denmark
Received 20 June 2007; revised 27 November 2007; accepted 7 January 2008; online publish-ahead-of-print 12 February 2008.
* Corresponding author: Lyøvej 18, 3.TV, DK-2000 Frederiksberg, Denmark. Tel: +45 38113340, Fax: +45 39760107, Email: ja{at}heart.dk
Aims: To explore the influence of obesity on prognosis in high-risk patients with myocardial infarction (MI) or heart failure (HF).
Methods and results: Individual data of 21 570 consecutively hospitalized patients from five Danish registries were pooled together. After a follow-up of 10.4 years, all-cause mortality using multivariate model and adjusted hazard ratios (HR) with 95% confidence intervals were calculated. Compared with normal weight [body mass index (BMI) 18.5–24.9 kg/m2], obesity class II (BMI 
35 kg/m2) was associated with increased risk of death in patients with MI but not HF [HR = 1.23 (1.06–1.44), P = 0.006 and HR = 1.13 (0.95–1.36), P = 0.95] (P-value for interaction = 0.004). Obesity class I (BMI 30–34.9 kg/m2) was not associated with increased risk of death in MI or HF [HR = 0.99 (0.92–1.08) and 1.00 (0.90–1.11), P > 0.1]. Pre-obesity (BMI 25–29.9 kg/m2) was associated with decreased death risk in MI but not HF [HR = 0.91 (0.87–0.96), P = 0.0006 and 1.04 (0.97–1.12), P = 0.34] (P-value for interaction = 0.007). Underweight (BMI < 18.5 kg/m2) patients were in increased death risk regardless of MI or HF [HR = 1.54 (1.35–1.75) and 1.37 (1.18–1.59), P < 0.001].
Conclusion: In patients with MI but not HF, the relationship between BMI and mortality is U-shaped with highest mortality in underweight and obese class II, but lowest in the other BMI classes.
Key Words: Obesity • Body mass index • Myocardial infarction • Heart failure