Low body mass index as a barrier to lung transplant in cystic fibrosis

Abstract

Rationale: Low body mass index (BMI) may influence lung transplant decisions for patients with advanced cystic fibrosis (CF) lung disease.

Objective: Determine whether patients with advanced CF lung disease and BMI ≤17 kg/m² are less likely to be listed for lung transplant or have a higher risk of death without listing compared to those with higher BMI.

Methods: Using merged United Network for Organ Sharing and CF Foundation Patient Registries, we identified adults with onset of advanced lung disease (FEV₁ ≤ 40% predicted) between May-2005 and December-2016. We analyzed survival using competing risks regression with cause-specific risks of listing for lung transplant and death without listing. BMI ≤ 17 kg/m² was our predictor.

Measurements and main results: Among 5,121 CF patients with advanced lung disease, 23% were listed for lung transplant (n = 1,201), 23% died without listing (n = 1,190), and 44% were alive without listing (n = 2,730) as of December-2016. Patients with BMI ≤ 17 kg/m² were less likely to be listed for transplant (HR 0.69; 95% CI 0.57, 0.83) and more likely to die without listing (HR 1.63; 95% CI 1.41, 1.88). We identified important regional variations in the likelihood of referral and listing, based on BMI.

Conclusions: Patients with advanced CF lung disease and BMI ≤ 17 kg/m² are less likely to be listed for lung transplant and have a higher risk of dying without listing, compared to those with higher BMI. Regional differences suggest access to transplant for malnourished CF patients may be limited by location.

Keywords: Lung diseases; Lung transplantation; Nutritional status; Survival analysis.