Oversimplified metrics?

An editorial in the American Journal of Transplantation questioned a proposed new “intention to treat survival” metric and suggested a composite of post-transplantation survival and waitlist survival metrics may better reflect the intended purpose.

The American Journal of Transplantation recently published interesting editorial comments (V von Berkel, 2018) on the dangers of oversimplification of quality metrics in lung transplantation.

The comments were in response to an article in the same issue of the journal by Moldenado et al, proposing a new metric: intention to treat survival (ITTS) which the authors define as the number of patients alive one year after transplantation, divided by the number of listed patients.

Von Berkel writes: “The concern is that a center may have excellent post-transplantation rates but are so selective in their decision-making regarding who gets transplanted that a given patient might be better served by going to an institution with a lower survival rate but a higher transplant rate”.

Moldenado´s ITTS combines one-year survival with the number of patients listed at an institution, in an effort to control for this effect. They conclude that while the median one-year survival after transplantation during the period they studied was 84%, the ITTS was 66.9% and that 12% of centers have a lower than expected ITTS: i.e. one third of lung transplant candidates do not survive one year after transplantation!

Von Berkel´s critical editorial however suggests a composite of post-transplantation survival and waitlist survival might better serve the intended purpose, and concludes that “…these are complex questions, which are not closely examined within the article.” Interesting food for thought, however, and not the first time the interpretation of statistics has evoked controversy – as Disraeli put it: “There are three kinds of lies: lies, damned lies, and statistics!”.


5. Moldenado et al, A novel patient-centered “intention-to-treat” metric of U.S. lung transplant center performance. Amer. J. Transplant. 18, 1, 226–231, Jan 2018 (link to abstract)
6. Berkel, The dangers of oversimplification – quality metrics and lung transplantation. Amer. J. Transplant. Vol. 18, 1, 11–12 . Jan 2018 (link to abstract)

Xvivo Insights PB-2018-01-28