Body composition, lung transplant candidacy, and patient outcomes

Underweight Patients With Cystic Fibrosis Have Acceptable Survival Following Lung Transplantation: A United Network for Organ Sharing Registry Study

BACKGROUND

Reduced BMI is an absolute contraindication for lung transplantation (LTx) at most centers in the United States. The objective of this study was to quantify post-LTx survival of moderate to severely underweight patients with cystic fibrosis (CF) (BMI < 17 kg/m²) in the United States relative to normal-weight recipients with CF and other frequently transplanted patient cohorts.

METHODS

Using United Network for Organ Sharing Registry data (undergoing transplant from June 2005-November 2015), Kaplan-Meier estimates of median posttransplant survival were calculated for all patients with CF, COPD, and idiopathic pulmonary fibrosis (IPF), as well as low and normal weight CF subgroups. Cox regression modeling stratified according to transplant center assessed risk of posttransplant mortality in recipients with CF and a BMI < 17 kg/m² compared with recipients with COPD (reference).

RESULTS

Median posttransplant survival (95% CI) for CF, COPD, and IPF was 7.9 (7.2-8.6), 5.9 (5.6-6.2), and 5.5 (5.2-5.8) years, respectively. Although an absolute decrease was noted in posttransplant survival for recipients with CF and a BMI < 17 kg/m², compared with those with CF and a BMI ≥ 17 kg/m² (7.0 years [4.5-7.9] vs 8.2 years [7.3-9.0]), Cox modeling found no increased mortality risk (adjusted hazard ratio, 1.09; 95% CI, 0.90-1.32; P = .38). There was no difference in posttransplant mortality between patients with CF and a BMI < 17 kg/m² and recipients with COPD and all BMIs (adjusted hazard ratio, 1.04; 95% CI, 0.86-1.25; P = .71).

CONCLUSIONS

Transplant recipients with CF and a BMI < 17 kg/m² had posttransplant survival rates comparable to those of other groups frequently undergoing transplantation. BMI < 17 kg/m² as a single risk factor in the CF population should not be treated as an absolute contraindication to LTx.