An acute change in lung allocation score and survival after lung transplantation: a cohort study

Abstract

Background: Lung transplantation is an effective treatment for patients with advanced lung disease. In the United States, lungs are allocated on the basis of the lung allocation score (LAS), a composite measure of transplantation urgency and utility. Clinical deteriorations result in increases to the LAS; however, whether the trajectory of the LAS has prognostic significance is uncertain.

Objective: To determine whether an acute increase in the LAS before lung transplantation is associated with reduced posttransplant survival.

Design: Retrospective cohort study of adult lung transplant recipients listed for at least 30 days between 4 May 2005 (LAS implementation) and 31 December 2010 in the United Network for Organ Sharing registry. An acute increase in the LAS was defined as an LAS change (LASΔ) greater than 5 units between the 30 days before and the time of transplantation. Multivariable Cox proportional hazard models were used to examine the relationship between an LASΔ >5 and posttransplant graft survival.

Setting: All U.S. lung transplantation centers.

Patients: 5749 lung transplant recipients.

Measurements: Survival time after lung transplantation.

Results: 702 (12.2%) patients experienced an LASΔ >5. These patients had significantly worse posttransplant survival (hazard ratio, 1.31 [95% CI, 1.11 to 1.54]; P = 0.001]) after adjustment for the LAS at transplantation (LAS-T) and other clinical covariates. The effect of an LASΔ >5 was independent of the LAS-T, underlying diagnosis, center volume, or donor characteristics.

Limitation: Analysis was based on center-reported data.

Conclusion: An acute increase in LAS before transplantation is associated with posttransplant survival after adjustment for LAS-T. Further emphasis on serial assessment of the LAS could improve the ability to offer accurate prediction of survival after transplantation.

Primary funding source: National Institutes of Health.

Figure 1

Study flow diagram. LAS = lung allocation score; UNOS = United Network for Organ Sharing.

Figure 2

Survival between LASΔ>5 and LASΔ≤5 cohorts by LAS at Transplant strata. The number of patients still at risk in each cohort is located above the horizontal axis.