Having a big belly increases the risk of death in heart attack survivors, according to research presented at ESC Congress 2013 by Professor Tabassome Simon and Professor Nicolas Danchin from France. The findings from the FAST-MI 2005 registry suggest that lifestyle interventions in heart attack patients should focus on losing abdominal fat.
Professor Simon said: "The impact of obesity on long term mortality and cardiovascular complications in the general population has been the object of recent debate. Much emphasis has also been given to the deleterious role of abdominal obesity."
She added: "At the time of a heart attack, early mortality tends to be lower in obese patients, a phenomenon well known in critical care situations and described as the 'obesity paradox'. Little is known, however, about the potential impact of obesity and abdominal obesity on long-term outcomes in patients who have survived the acute stage of a heart attack."
The current study sought to determine the associations between body mass index (BMI, kg/m2) and waist circumference with 5-year mortality in patients of the FAST-MI 2005 registry who had left the hospital alive.
FAST-MI 2005 is a French nationwide survey which included 3,670 patients from 223 institutions who were admitted for acute myocardial infarction to an intensive care unit at the end of 2005. Long-term follow-up was achieved in 99.6% at one year, 98% at 3 years, and 95% at 5 years. Of the 3,463 patients who were discharged alive, BMI was recorded in 3,102 and waist circumference in 1,647 patients. Statistical techniques were used to take into account the differences in baseline characteristics between the different BMI groups.
At 5 years, absolute mortality was highest in the leanest patients (BMI <22 kg/m²) and lowest in patients with BMI between 25 and 35 kg/m² (i.e. overweight and mild obesity). Patients with severe obesity (BMI ≥ 35 kg/m²) had a markedly increased mortality after 3 years (Figure 1). Severe abdominal obesity (waist circumference >100 cm in women and >115 cm in men) was also associated with increased long-term mortality (Figure 2).
Professor Simon said: "As waist circumference is strongly linked to BMI, we determined the upper quartile of waist circumference (i.e. quarter of the population with the highest waist circumference) within each BMI category and used both variables together to determine their respective role in association with long-term mortality."
She continued: "We found that both lean patients (BMI <22 kg/m²) and very obese patients (BMI ≥35 kg/m²) had an increased risk of death at 5 years: + 41% and + 65%, respectively. Being in the upper quartile of waist circumference (i.e. having a big belly considering your weight) was also an indicator of increased mortality at 5 years (+ 44%)."
Figure 3 shows the U-curve observed for risk of 5-year mortality according to baseline BMI. The risk of death at 5 years was the lowest for BMI between 22 and 35 kg/m².
Professor Simon concluded: "High waist circumference, severe obesity and underweight are associated with the greatest risk of death in heart attack survivors. It is not good to be too lean or too fat, but it is worse still when you have a big belly. From a public health standpoint, educational messages in patients having sustained a heart attack should focus more on the most severe forms of obesity and abdominal obesity and on other risk factors (such as smoking and being sedentary), rather than on overweight and mild obesity."