A Longitudinal Renal Health Outcome for Clinical Trials in Acute Kidney Injury?

Given how you’ve already branded your effort, it may be too late to advise against setting out presumptively to define any One Outcome to Rule Them All. Still, I think it so much more fruitful scientifically to start from scientific questions, and to construct outcomes specifically adapted to them.

If you wish to advance a unifying perspective, seek this in a general formalism rather than a standard outcome. For such a formalism in this problem setting, I would reach for state-space modeling and particle filtering methods [1,2]. Of all the organs, kidney physiology surely has the richest theoretical basis; the modeling opportunities here should be marvelous. (Also, how could nephrologists not love filtering? )

1. Künsch HR. Particle filters. Bernoulli. 2013;19(4):1391-1403. doi:10.3150/12-BEJSP07

2. Kantas N, Doucet A, Singh SS, Maciejowski J, Chopin N. On Particle Methods for Parameter Estimation in State-Space Models. Statist Sci. 2015;30(3):328-351. doi:10.1214/14-STS511