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. 2014 Oct;14(10):2288-94.
doi: 10.1111/ajt.12903. Epub 2014 Sep 10.

Impact of the lung allocation score on survival beyond 1 year

B G Maxwell  1 , J E Levitt, B A Goldstein, J J Mooney, M R Nicolls, M Zamora, V Valentine, D Weill, G S Dhillon
Affiliations

Impact of the lung allocation score on survival beyond 1 year

B G Maxwell et al. Am J Transplant. 2014 Oct.

Abstract

Implementation of the lung allocation score (LAS) in 2005 led to transplantation of older and sicker patients without altering 1-year survival. However, long-term survival has not been assessed and emphasizing the 1-year survival metric may actually sustain 1-year survival while not reflecting worsening longer-term survival. Therefore, we assessed overall and conditional 1-year survival; and the effect of crossing the 1-year threshold on hazard of death in three temporal cohorts: historical (1995-2000), pre-LAS (2001-2005) and post-LAS (2005-2010). One-year survival post-LAS remained similar to pre-LAS (83.1% vs. 82.1%) and better than historical controls (75%). Overall survival in the pre- and post-LAS cohorts was also similar. However, long-term survival among patients surviving beyond 1 year was worse than pre-LAS and similar to historical controls. Also, the hazard of death increased significantly in months 13 (1.44, 95% CI 1.10-1.87) and 14 (1.43, 95% CI 1.09-1.87) post-LAS but not in the other cohorts. While implementation of the LAS has not reduced overall survival, decreased survival among patients surviving beyond 1 year in the post-LAS cohort and the increased mortality occurring immediately after 1 year suggest a potential negative long-term effect of the LAS and an unintended consequence of increased emphasis on the 1-year survival metric.

Keywords: Clinical research/practice; Scientific Registry for Transplant Recipients (SRTR); ethics; health services and outcomes research; lung transplantation/pulmonology; organ allocation; organ transplantation in general; patient survival; risk assessment/risk stratification; social sciences.

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Figures

Figure 1
Figure 1. Overall survival by cohort
Kaplan–Meier survival curves for the three cohorts: historical control (1995–2000) (red line); pre-LAS (2001–4/2005) (blue line); and post-LAS (5/2005–6/2010) (green line). Panel A—full curves out to 1095 days; Panel B—expanded curves (area outlined in Panel A) centered on the 1-year time point (dashed black line) out to 1.5 years.
Figure 2
Figure 2. Conditional survival by cohort
Kaplan–Meier survival curves conditioned on survival to 1-year posttransplantation for the three cohorts: historical control (1995–2000) (red line); pre-LAS (2001–4/2005) (blue line); and post-LAS (5/2005–6/2010) (green line). Panel A—full curves out to 1095 days; Panel B—expanded curves (area outlined in Panel A) starting at the 1-year time point (dashed black line) out to 1.5 years.
Figure 3
Figure 3. Hazard ratio for mortality after 1 year
Point estimates (circles) with 95% confidence intervals (error bars) for the hazard ratio of mortality in each month after 1 year compared to a baseline hazard calculated for the 90 days period prior to 1 year for the three cohorts: historical control (1995–2000) (red line); pre-LAS (2001–4/2005) (green line); and post-LAS (5/2005–6/2010) (blue line). *denotes significance at p <0.05.
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