Obesity Definitions and Hospital Stay in Older Adults with Heart Failure: A Post Hoc Analysis of a Prospective Cohort

The prognostic significance of obesity in patients hospitalised for acute heart failure (HF) remains uncertain, particularly among older adults. This study aimed to assess whether three obesity definitions - BMI, waist circumference and the clinical obesity framework - predict hospital length of stay (LOS) in older adults hospitalised for acute decompensated HF.

This post hoc exploratory analysis used data from a prospective cohort of 250 adults aged ≥60 years hospitalised for acute decompensated HF. Obesity was defined as: BMI ≥30 kg/m²; waist circumference ≥102 cm in men or ≥88 cm in women; and clinical obesity per the Lancet Diabetes & Endocrinology Commission, applied post hoc. LOS was modelled using univariable and multivariable negative binomial regression.

None of the three obesity definitions were independently associated with LOS. In the multivariable models, only N-terminal pro-B-type natriuretic peptide (NT-proBNP) was an independent predictor of LOS in patients with clinical obesity (incidence rate ratio [IRR] 1.004 per 100 pg/ml; p=0.004). Among those with classical obesity, New York Heart Association class IV (IRR 2.355; p=0.004), NT-proBNP (IRR 1.004; p=0.004), and smoking history of 41-50 pack-years (IRR 1.946; p=0.022) remained independently associated with longer LOS. For central obesity, haemoglobin (IRR 0.923; p=0.029) and NT-proBNP (IRR 1.004; p<0.001) were significant predictors.

In this cohort of older adults hospitalised for acute decompensated HF, none of the three obesity definitions - including the new clinical obesity framework - were independent predictors of LOS.