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The Effect of Augmenting OPTN Data With External Death Data on Calculating Patient Survival Rates After Organ Transplantation

Wilk, Amber R. PhD; Edwards, Leah B. PhD; Edwards, Erick B. PhD

doi: 10.1097/TP.0000000000001448
Original Clinical Science—General

Background Although the Organ Procurement and Transplantation Network (OPTN) database contains a rich set of data on United States transplant recipients, follow-up data may be incomplete. It was of interest to determine if augmenting OPTN data with external death data altered patient survival estimates.

Methods Solitary kidney, liver, heart, and lung transplants performed between January 1, 2011, and January 31, 2013, were queried from the OPTN database. Unadjusted Kaplan-Meier 3-year patient survival rates were computed using 4 nonmutually exclusive augmented datasets: OPTN only, OPTN + verified external deaths, OPTN + verified + unverified external deaths (OPTN + all), and an additional source extending recipient survival time if no death was found in OPTN + all (OPTN + all [Assumed Alive]). Pairwise comparisons were made using unadjusted Cox Proportional Hazards analyses applying Bonferroni adjustments.

Results Although differences in patient survival rates across data sources were small (≤1 percentage point), OPTN only data often yielded slightly higher patient survival rates than sources including external death data. No significant differences were found, including comparing OPTN + verified (hazard ratio [HR], 1.05; 95% confidence interval [95% CI], 1.00-1.10); P = 0.0356), OPTN + all (HR, 1.06; 95% CI, 1.01-1.11; P = 0.0243), and OPTN + all (Assumed Alive) (HR, 1.00; 95% CI, 0.96-1.05; P = 0.8587) versus OPTN only, or OPTN + verified (HR, 1.05; 95% CI, 1.00-1.10; P = 0.0511), and OPTN + all (HR, 1.05; 95% CI, 1.00-1.10; P = 0.0353) versus OPTN + all (Assumed Alive).

Conclusions Patient survival rates varied minimally with augmented data sources, although using external death data without extending the survival time of recipients not identified in these sources results in a biased estimate. It remains important for transplant centers to maintain contact with transplant recipients and obtain necessary follow-up information, because this information can improve the transplantation process for future recipients.

Differences in patient survival rates at 3 years using OPTN data are higher than OPTN plus augmented data, but the difference is less than 1 percentage point, validating the utility of OPTN survival data.

1 United Network for Organ Sharing (UNOS), Richmond, VA.

Received 11 January 2016. Revision received 21 July 2016.

Accepted 22 July 2016.

This work was supported wholly or in part by Health Resources and Services Administration (HRSA) contract 234-2005-370011C. The content is the responsibility of the authors alone and does not necessarily reflect the views or policies of the Department of HHS, nor does mention of trade names, commercial products, or organizations imply endorsement by the U.S. Government.

The authors declare no conflicts of interest.

The data reported here have been supplied by the United Network for Organ Sharing (UNOS) as the contractor for the Organ Procurement and Transplantation Network (OPTN). The interpretation and reporting of these data are the responsibility of the author(s) and in no way should be seen as an official policy of or interpretation by the OPTN or the U.S. Government.

A.R.W. participated in research design, data analysis, and drafting the article. L.B.E. participated in research design and drafting the article. E.B.E. participated in research design and drafting the article.

Correspondence: Amber R. Wilk, PhD, United Network for Organ Sharing (UNOS) 700 North 4th Street, Richmond, VA 23219. (Amber.Wilk@unos.org).

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