IMHO, this is the best on-line informational site regarding canine kidney health issues.  It not only cover the kidney condition, it also gives you a list of foods and their relation to other foods deemed acceptable for kidney diets.

http://dogaware.com/health/kidney.html

this particular page is especially most helpful: http://dogaware.com/health/kidneytable.html 

With and EPI + Kidney dog….. the diet may need to be slightly modified…..if you have to use ingredients not that agreeable with the EPI … you can still effectively manage EPI via more enzymes and ‘tweaking” the amount of various ingredients in the kidney diet.

This is an overview of the contents of this link: