The combined effects of obesity and malnutrition among individuals with heart failure were explored in this recent study from France, with the investigators noting that while malnutrition is a risk factor for adverse outcomes, obesity often confers a protective effect.
Compared with 3 classifications of nutritional status—normal, obese, and obese-malnutrition—malnutrition among individuals with heart failure was shown to have a significant adverse effect on overall life expectancy, according to new study findings from France.
In addition, patients with chronic heart failure who were classified as both malnourished and obese had similar life expectancies compared with patients with the disease and a normal nutritional status.
These findings were published in Nutritional Journal.
While malnutrition is a risk factor for adverse outcomes among persons with heart failure, obesity often confers a protective effect, the authors noted. However, the effects of the interaction between obesity and malnutrition on patient mortality from heart failure are not well understood, which spurred this retrospective study. All patients 18 years and older with a principal diagnosis of heart failure between 2021 and 2016 from a French acute care hospital (public or private) were included in the analysis. International Classification of Diseases, Tenth Revision code 150 confirmed heart failure diagnosis.
“Malnutrition is a risk factor for mortality, whereas obesity may play a protective role, a phenomenon dubbed the ‘obesity paradox,” the authors explained. “However, the effect of the obesity-malnutrition association on mortality has not been previously studied.”
Overall, when comparing outcomes between patients with chronic heart failure and normal, obese, and obese-malnutrition status, malnutrition alone was linked to a 16% greater chance of reduced life expectancy (adjusted HR [aHR], 1.16; 95% CI, 1.14-1.18) at the 1-year mark following heart failure diagnosis and a 4% greater risk at the 4-year mark (aHR, 1.04; 95% CI, 1.004-1.08).
In contrast, obesity was associated with a 25% reduced risk of death at 1 year (aHR, 0.75; 95% CI, 0.73-0.78) and 15% at 4 years (aHR, 0.85; 95% CI, 0.81-0.90).
Observed mortality rates, meanwhile, were lowest at both the 1- and 4-year marks for the obese group and highest at these points for the malnutrition group:
“In the malnutrition-only group, the more severe the malnutrition, the lower the probability of survival,” the authors emphasized. “In the obesity-only group, all classes of obesity had better survival than nonobese groups.” For example, whereas severe obesity increased the risk of in-hospital death 46% at 4 years (aHR, 1.46; 95% CI, 1.38-1.55), morbid obesity decreased that risk 35% (aHR, 0.65; 95% CI, 0.58-0.72).
Most patients in this analysis were classified as having severe or moderate malnutrition and standard (body mass index [BMI], 30-40 kg/m2) or morbid (BMI, 40-50 kg/m2) obesity. Malnutrition criteria also varied for the patients, with patients younger than 70 years and 70 years and older having to meet at least 1 of different criteria:
Because the authors’ findings contradict some of the published literature, particularly studies from the United States they highlight—which they attribute to diet and physical activity differences between the 2 countries—future studies need to explore the obesity paradox, especially in regard to morbid obesity.
However, this does not take away from the importance of their findings because they also reiterate findings from previous studies on obesity’s protective role and the body’s adverse reaction to malnutrition among persons living with heart failure. The main strengths of these findings lie in the use of a national database for data sampling and long follow-up times, and principal limitations include only measuring in-hospital mortality and using just 1 database (the French hospital discharge abstract database, or Programme de Médicalisation des Systèmes d’Informations) for nutritional status.
“Further studies are needed to explore the possible protective effect of increased body fat during heart failure, and further interventional studies should be conducted to confirm our results,” the authors concluded. “It would also be worthwhile to explore the physiopathological mechanisms that could explain this effect in more detail.”
Carime NA, Cottenet J, Clerfond G, et al. Impact of nutritional status on heart failure mortality: a retrospective cohort study. Nutr J. Published online January 6, 2022. doi:10.1186/s12937-021-00753-x