Impact of weight on long-term survival among patients without known coronary artery disease and a normal stress SPECT MPI

Division of Cardiology, Department of Medicine, St. Luke's and Roosevelt Hospitals, Columbia University College of Physicians and Surgeons, 1111 Amsterdam Avenue, New York, NY, USA.
Journal of Nuclear Cardiology (Impact Factor: 2.94). 03/2010; 17(3):390-7. DOI: 10.1007/s12350-010-9214-6
Source: PubMed

ABSTRACT While obesity has been shown to be associated with a worse mortality, an "obesity paradox"--lower mortality in obese patients--has been noted among many patients with coronary artery disease (CAD). The extent to which an obesity paradox operates among patients with only suspected CAD, is not well determined.
A total of 3,673 patients (60 +/- 13 years, 36% males) with no history of heart disease and a normal stress SPECT were included in this study. Normal weight was defined as BMI of 18.5-24.9 kg x m(2); overweight 25-29.9 kg . m(2), obese >30 kg x m(2). The baseline clinical risk factors were recorded for each patient. The end point of the study was all-cause mortality. Of patients 942 (26%) were normal weight, 1,261 (34%) were overweight, and 1,470 (40%) were obese. Mean patient follow-up was 7.5 +/- 3 years. When compared to normal weight patients (event rate 3.2%/year), there was a lower incidence of death in the overweight (event rate 1.5%/year, P < .0001) and the obese (event rate 1.2%/year, P < .0001) groups. After controlling for baseline risk factors, using a reference HR = 1 for normal weight patients, there was a lower risk of death in the overweight (HR = .54, 95% CI .43-.7) and the obese groups (HR = .49, 95% CI .38-.63).
In patients without known cardiac disease and a normal stress SPECT, overweight and obese patients had a lower rate of all-cause mortality compared to normal weight patients over long-term follow-up. This study substantially extends the spectrum of patients in whom the obesity paradox is present.

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    • "Hazard Ratios for All - Cause Mortality Relative to Normal Weight in Studies That Used Measured Data for Participants With a Body Mass Index of 30 or Greater 5 1 . 0 0 . 1 Hazard Ratio ( 95% CI ) Source Stessman et al , 35 2009 ( women ) Uretsky et al , 36 2010 Lisko et al , 33 2011 ( men ) Iribarren et al , 45 2005 Luchsinger et al , 24 2008 Cabrera et al , 65 2005 Lisko et al , 33 2011 ( women ) Janssen , 55 2007 Visscher et al , 38 2004 ( women ≥65 "
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    ABSTRACT: Estimates of the relative mortality risks associated with normal weight, overweight, and obesity may help to inform decision making in the clinical setting. To perform a systematic review of reported hazard ratios (HRs) of all-cause mortality for overweight and obesity relative to normal weight in the general population. PubMed and EMBASE electronic databases were searched through September 30, 2012, without language restrictions. Articles that reported HRs for all-cause mortality using standard body mass index (BMI) categories from prospective studies of general populations of adults were selected by consensus among multiple reviewers. Studies were excluded that used nonstandard categories or that were limited to adolescents or to those with specific medical conditions or to those undergoing specific procedures. PubMed searches yielded 7034 articles, of which 141 (2.0%) were eligible. An EMBASE search yielded 2 additional articles. After eliminating overlap, 97 studies were retained for analysis, providing a combined sample size of more than 2.88 million individuals and more than 270,000 deaths. Data were extracted by 1 reviewer and then reviewed by 3 independent reviewers. We selected the most complex model available for the full sample and used a variety of sensitivity analyses to address issues of possible overadjustment (adjusted for factors in causal pathway) or underadjustment (not adjusted for at least age, sex, and smoking). Random-effects summary all-cause mortality HRs for overweight (BMI of 25-<30), obesity (BMI of ≥30), grade 1 obesity (BMI of 30-<35), and grades 2 and 3 obesity (BMI of ≥35) were calculated relative to normal weight (BMI of 18.5-<25). The summary HRs were 0.94 (95% CI, 0.91-0.96) for overweight, 1.18 (95% CI, 1.12-1.25) for obesity (all grades combined), 0.95 (95% CI, 0.88-1.01) for grade 1 obesity, and 1.29 (95% CI, 1.18-1.41) for grades 2 and 3 obesity. These findings persisted when limited to studies with measured weight and height that were considered to be adequately adjusted. The HRs tended to be higher when weight and height were self-reported rather than measured. Relative to normal weight, both obesity (all grades) and grades 2 and 3 obesity were associated with significantly higher all-cause mortality. Grade 1 obesity overall was not associated with higher mortality, and overweight was associated with significantly lower all-cause mortality. The use of predefined standard BMI groupings can facilitate between-study comparisons.
    JAMA The Journal of the American Medical Association 01/2013; 309(1):71-82. DOI:10.1001/jama.2012.113905 · 35.29 Impact Factor
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    • "Despite all these adverse associations, numerous studies and meta-analyses have documented an ''obesity paradox " in which overweight and obese population with established cardiovascular disease (CAD, HT and HF) have a better prognosis than do their lean counterparts; and that obesity has not been associated with a worse outcome in all patient populations [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19]. In a systematic review of 40 studies including a total of >250,000 patients with CAD, a better outcome for cardiovascular and total mortality was seen in the overweight and mildly obese groups compared with normal-weight patients [16] [17]. "
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    ABSTRACT: Obesity has reached global pandemic that threatens the health of millions of people and is associated with numerous morbidities such as hypertension, type II diabetes mellitus, dyslipidemia, cor pulmonale, gallbladder disease, obstructive sleep apnea (OSA), certain cancers, osteoarthritis, increased surgical risk and postoperative complications, lower extremity venous and/or lymphatic problems, pulmonary embolism, stroke/cerebrovascular diseases and coronary arterial disease. Despite all these adverse associations, numerous studies and meta-analyses have documented an "obesity paradox" in which overweight and obese population with established cardiovascular disease have a better prognosis than do their lean counterparts. There are potential and plausible explanations offered by literature for these puzzling data; however, it still remains uncertain whether this phenomenon is attributable to a real protective effect of high body fat mass. In recent years, the survival advantage of patients with OSA, combined with the potential cardioprotective effects of chronic intermittent hypoxia, raise the possibility that apneas during sleep may activate preconditioning-like cardioprotective effect. Chronic intermittent hypoxia, one of the physiological markers of OSA, is characterized by transient periods of oxygen desaturation followed by reoxygenation, and is a major cause of its systemic harmful (oxidative stress, inflammation, sympathetic activity, vasculature remodelling and endothelial dysfunction) and/or protective (preconditioning-like cardioprotective) effects. Since many OSA subjects are obese, and obesity is an independent risk factor for many comorbidities associated with OSA; and also most OSA has never been diagnosed in obese patients, we hypothesed that the chronic intermittent hypoxia caused by OSA in obese patients may be one of the underlying mechanisms in morbi-mortality paradox of obesity.
    Medical Hypotheses 01/2011; 76(1):61-3. DOI:10.1016/j.mehy.2010.08.030 · 1.07 Impact Factor
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