U- shaped relationship observed between BMI and mortality due to heart failure

Obesity and Heart Failure (HF) is most closely linked to each other factors causing various complications such as hypertension, left ventricular hypertrophy, inflammation, hyperglycemia, sleep-disordered breathing, and renal dysfunction. However there is limited evidence in community populations across long-term follow-up.

Nicholas R Jones and team of researchers in a recent study aimed to examine the association between BMI and long-term survival in patients with HF in a large primary care cohort. The study reveals a U-shaped relationship between BMI and long-term all-cause mortality, researchers suggest a personalised approach to identifying optimal weight may be needed for patients with HF in primary care. Underweight people have the poorest prognosis and should be recognised as high-risk. The findings are published in journal Heart.

Study included patients with incident HF aged ≥45 years from the Clinical Practice Research Datalink (2000–2017). They used Kaplan-Meier curves, Cox regression and penalised spline methods to assess the association of pre-diagnostic BMI, based on WHO classification, with all-cause mortality.

The findings of the study are

• Out of 47 531 participants with HF (median age 78.0 years (IQR 70–84), 45.8% female, 79.0% white ethnicity, median BMI 27.1 (IQR 23.9–31.0)) and 25 013 (52.6%) died during follow-up.

• Compared with healthy weight, people with overweight (HR 0.78, 95% CI 0.75 to 0.81, risk difference (RD) −4.1%), obesity class I (HR 0.76, 95% CI 0.73 to 0.80, RD −4.5%).

• class II (HR 0.76, 95% CI 0.71 to 0.81, RD −4.5%) were at decreased risk of death, whereas people with underweight were at increased risk (HR 1.59, 95% CI 1.45 to 1.75, RD 11.2%).

• In those underweight, this risk was greater among men than women (p value for interaction=0.02).

• Class III obesity was associated with increased risk of all-cause mortality compared with overweight (HR 1.23, 95% CI 1.17 to 1.29).

Jones and team concluded that “The U-shaped relationship between BMI and long-term all-cause mortality suggests a personalised approach to identifying optimal weight may be needed for patients with HF in primary care. Underweight people have the poorest prognosis and should be recognised as high-risk.”

Reference: Jones NR, Ordóñez-Mena JM, Roalfe AK, et al; Body mass index and survival in people with heart failure, Heart Published Online First: 08 June 2023. doi: 10.1136/heartjnl-2023-322459