The importance of body mass index and weight-change in patients with coronary artery disease

Research output: ThesisDoctoral Thesis (compilation)

Abstract

High body mass index (BMI) is associated with cardiovascular risk factors such as hypertension, dyslipidemia, and insulin resistance. Obesity is also an independent risk factor for coronary artery disease (CAD) and can cause structural as well as functional changes in the heart. High BMI is associated with increased mortality in the population. Weight-loss from a state of overweight or obesity may reverse some of the alternations associated with excess weight. However, the survival benefit of weight-loss among the population is still uncertain.

The aims of this thesis were to examine the prognostic importance of BMI and weight-change in patients with CAD. A total of 12 550 patients with CAD, 94% with prior acute myocardial infarction (AMI), were included in our post-hoc analyses. Patients were recruited from 3 large clinical trials in which weight and height were measured. Mean follow-up ranged from 6 months to 5.4 years. Patients were categorized into 4 groups according to baseline BMI: underweight (< 22.00 kg/m2), normal-weight (22.00-24.99 kg/m2), overweight (25.00-29.99 kg/m2), obese (>/= 30 kg/m2). Patients were divided into 3 groups with regard to weight-change; weight-loss, weight-stability and weight-gain. Weight-change was pre-defined as weight-gain or weight-loss from baseline of > 0.1 kg per baseline BMI-unit. Consequently, for a patient with a BMI of 25 kg/m2, a change of > ±2.5 kg was categorized as a weight-change. This corresponds to 3-3.5% change in total body-weight. Weight-change was assessed after 3-12 months.

One of the main findings in this thesis was that among patients with CAD, being overweight or obese was not associated with increased mortality or morbidity risk, compared to being normal-weight. Being underweight was significantly associated with increased mortality risk compared to being normal-weight. The prognostic impact of BMI was related to time of follow-up as well as the inherent risk of the patient. It seems that obesity might be hazardous during longer period of follow-up and when the inherent risk of the patient is low.

Another finding is that the association between BMI and prognosis was related to treatment with neurohormonal blockade, i.e. ACE inhibitors and betablockers. Increased activation of the renin angiotensin system and the sympathetic nervous system is common in patients with CAD. Being overweight or obese was associated with decreased survival among patients not receiving neurohormonal blockade. Among patients receiving neurohormonal blockade, overweight and obese patients did not have increased mortality compared to normal-weight patients.

Weight-loss was not associated with survival benefits among patients with CAD. Compared to weight-stability, weight-loss was rather associated with increased mortality, independent of baseline BMI. Weight-gain had similar risk compared to weight-stability. The reasons for these observations are likely multifactorial. Importantly, our findings do not preclude a benefit of weight-loss in response to exercise training as part of a cardiac rehabilitation program.

Our observations expand the knowledge about how BMI and body weight-change are related to the prognosis in patients with stable CAD and following AMI. These findings reinforce the need for a better understanding of the importance of BMI and the complexity of weight-change to the prognosis among these patients. Our data do not indicate that obesity is a negative factor in patients with CAD today, whereas underweight is. Further, our observations indicate that weight-loss in patients with established CAD should render every doctor's attention and underlying reasons should be explored. These associations and their causes should be further assessed in future investigations. Meanwhile, we believe that our main focus should be on preventing obesity early in life. In other words, obesity should be prevented rather than treated.
Original languageEnglish
QualificationDoctor
Awarding Institution
  • Department of Clinical Sciences, Malmö
Supervisors/Advisors
  • Willenheimer, Ronnie, Supervisor
Award date2006 May 23
Publisher
Print ISBNs91-85481-96-3
Publication statusPublished - 2006

Bibliographical note

Defence details

Date: 2006-05-23
Time: 13:00
Place: Medicinska Klinikens aula, ingång 35, Universitetssjukhuset MAS, Malmö

External reviewer(s)

Name: Coats, Andrew
Title: Professor
Affiliation: Faculty of Medicine, University of Sydney, Australia

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<div class="article_info">LM Kennedy, K Dickstein, SD Anker, K Kristianson and R Willenheimer. <span class="article_issue_date">2005</span>. <span class="article_title">The prognostic importance of body mass index after complicated myocardial infarction.</span> <span class="journal_series_title">OPTIMAAL Study Group. J Am Coll Cardiol.</span>, <span class="journal_volume">vol 45</span> <span class="journal_pages">pp 156-158</span>.</div>
<div class="article_info">Linn M A Kennedy, Tom Cook, Kenneth Dickstein, Stefan D Anker, John Kjekshus and Ronnie Willenheimer. <span class="article_issue_date"></span>. <span class="article_title">The prognostic importance of body mass index in patients with coronary artery disease: Effect of time of follow-up, age, sex and inherent risk.</span> (manuscript)</div>
<div class="article_info">Linn M A Kennedy, Stefan D Anker, John Kjekshus, Tom J Cook and Ronnie Willenheimer. <span class="article_issue_date">2006</span>. <span class="article_title">Impact of Neurohormonal Blockade on Association Between Body Mass Index and Mortality.</span> <span class="journal_series_title">International Journal of Cardiology</span>, (submitted)</div>
<div class="article_info">Linn M A Kennedy, Kenneth Dickstein, Stefan D Anker, Margaret James, Thomas J Cook, Krister Kristianson and Ronnie Willenheimer. <span class="article_issue_date">2005</span>. <span class="article_title">Weight-change as a prognostic marker in 12 550 patients following acute myocardial infarction or with stable coronary artery disease.</span> <span class="journal_series_title">European Heart Journal</span>, (submitted)</div>


The information about affiliations in this record was updated in December 2015.
The record was previously connected to the following departments: Emergency medicine/Medicine/Surgery (013240200)

Subject classification (UKÄ)

  • Clinical Medicine

Keywords

  • Medicine (human and vertebrates)
  • Cardiovascular system
  • Medicin (människa och djur)
  • Kardiovaskulära systemet
  • prognosis
  • coronary artery disease
  • body mass index

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