Body Composition

Alternative Measures of Body Composition and Outcomes Following Heart Transplant.

TL;DR

Although BMI does not predict mortality post-HT, it can differentiate risk better than all other metrics, with highest and lowest BMI tertiles associated with increased rates of hospital readmission and infection in the first-year post HT.

Key Findings

Both the highest and lowest BMI tertiles were significantly associated with increased risk of hospital readmission within 1 year post heart transplant.

  • Highest BMI tertile: OR 3.4, 95% CI 1.1–11.4; lowest BMI tertile: OR 5.9, 95% CI 1.7–25.1; p = 0.01
  • This U-shaped association indicates both extremes of BMI confer elevated readmission risk
  • Study included 104 patients who underwent heart transplant between 2014 and 2019
  • Body composition was assessed using CT scans performed within 3 months of transplant analyzed with Slice-O-Matic software

Both the highest and lowest BMI tertiles were significantly associated with increased risk of infections requiring hospitalization within 1 year post heart transplant.

  • Highest BMI tertile: OR 3.2, 95% CI 1.2–9.0; lowest BMI tertile: OR 3.9, 95% CI 1.4–11.7; p = 0.02
  • This association was identified through univariate and multivariate logistic regression analyses
  • The cohort was 80% male and 56% Caucasian

Alternative body composition measures including fat mass index (FMI), visceral-to-subcutaneous adipose tissue ratio (VAT/SAT), fat free mass index (FFMI), and skeletal muscle index (SMI) were not associated with outcomes 1 year post heart transplant.

  • Outcomes examined included 1-year mortality, readmission, primary graft dysfunction, length of stay, infection, and renal failure
  • None of FMI, VAT/SAT, FFMI, or SMI showed statistically significant associations with any of these outcomes
  • These measures were derived from abdominal CT scans using Slice-O-Matic software
  • Analyses were performed by tertiles using univariate and multivariate logistic regression

BMI was not associated with 1-year mortality post heart transplant.

  • Despite associations with readmission and infection, BMI did not predict mortality at 1 year
  • This finding is consistent with the paper's characterization that 'data supporting this recommendation is mixed' regarding the BMI < 35 kg/m² listing guideline
  • The study examined outcomes in 104 patients over the period 2014–2019

Current heart transplant listing guidelines support a BMI threshold of less than 35 kg/m², but the evidence base for this recommendation is described as mixed.

  • The guideline specifies BMI < 35 kg/m² for heart transplant listing
  • The authors note it is unclear whether more specific measurements of body composition are better predictors of post-transplant outcomes
  • This uncertainty motivated the investigation of alternative body composition metrics derived from CT imaging

The study cohort consisted of 104 patients who underwent heart transplant between 2014 and 2019 and had abdominal CT scans within 3 months of transplant.

  • 80% of patients were male and 56% were Caucasian
  • This was a retrospective study design
  • Body composition variables analyzed included BMI, FMI, VAT/SAT ratio, FFMI, and SMI
  • Analyses used univariate and multivariate logistic regression with variables grouped by tertiles

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Citation

Lanier A, Siddiqi U, Siddiqi U, Lee L, Saffari S, Belkin M, et al.. (2026). Alternative Measures of Body Composition and Outcomes Following Heart Transplant.. Clinical transplantation. https://doi.org/10.1111/ctr.70448