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The Journal of Heart and Lung Transplantation
International Society for Heart and Lung Transplantation.

Assessing the accuracy of the lung allocation score

  • Author Footnotes
    # denotes equal contribution to the manuscript
    William F. Parker
    Correspondence
    Reprint requests: William F Parker MD, PhD, Department of Medicine, University of Chicago, 5841 S Maryland Avenue, MC 6076, Chicago, IL 60637. Telephone: 847-525-4924, Office: 773-702-1092. Fax: 773- 703-6500.
    Footnotes
    # denotes equal contribution to the manuscript
    Affiliations
    Department of Medicine, Section of Pulmonary and Critical Care Medicine, University of Chicago, Chicago, Illinois

    MacLean Center for Clinical Medical Ethics, University of Chicago, Chicago, Illinois
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  • Author Footnotes
    # denotes equal contribution to the manuscript
    Nicole E. Dussault
    Footnotes
    # denotes equal contribution to the manuscript
    Affiliations
    Pritzker School of Medicine, University of Chicago, Chicago, Illinois
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  • Renea Jablonski
    Affiliations
    Department of Medicine, Section of Pulmonary and Critical Care Medicine, University of Chicago, Chicago, Illinois
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  • Edward R. Garrity
    Affiliations
    Department of Medicine, Section of Pulmonary and Critical Care Medicine, University of Chicago, Chicago, Illinois

    MacLean Center for Clinical Medical Ethics, University of Chicago, Chicago, Illinois
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  • Matthew M. Churpek
    Affiliations
    Department of Medicine, Division of Pulmonary and Critical Care Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
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  • Author Footnotes
    # denotes equal contribution to the manuscript
Published:October 27, 2021DOI:https://doi.org/10.1016/j.healun.2021.10.015

      BACKGROUND

      The United States (US) Lung Allocation Score (LAS) relies on the performance of 2 survival models that estimate waitlist and post-transplant survival. These models were developed using data from 2005 to 2008, and it is unknown if they remain accurate.

      METHODS

      We performed an observational cohort study of US lung transplantation candidates and recipients greater than 12 years of age between February 19, 2015 and February 19, 2019. We evaluated the LAS waitlist and post-transplant models with the concordance probability estimate and by comparing predicted vs observed 1-year restricted mean survival times by risk decile. We then compared a nonparametric estimate of the observed LAS with the predicted LAS for each percentile of recipients.

      RESULTS

      The waitlist model ranked candidates (N = 11,539) in the correct risk order 72% of the time (95% CI 71%-73%), and underestimated candidate one-year survival by 136 days for the highest risk decile (p < 0.001). The post-transplant model ranked recipients (N = 9,377) in the correct risk order 57% of the time (95% CI 55-58%), and underestimated recipient one-year survival by 70 days for the highest risk decile (p < 0.001). Overall, the LAS at transplant explained only 56% of the variation in observed outcomes, and was increasingly inaccurate at higher predicted values.

      CONCLUSIONS

      The waitlist and the post-transplant models that constitute the LAS are inaccurate, limiting the ability of the system to rank candidates on the waitlist in the correct order. The LAS should therefore be updated and the underlying models should be modernized.

      Keywords

      Abbreviations:

      CI (Confidence Interval), CPE (Concordance Probability Estimate), FiO2 (Fraction of Inspired Oxygen), LAS (Lung Allocation Score), OPTN (Organ Procurement and Transplantation Network), pCO2 (Partial Pressure of Carbon Dioxide), PTAUC (Post-transplant Area Under the Curve), SRTR (Scientific Registry of Transplant Recipients), US (United States), WLAUC (Waitlist Area Under the Curve)
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