What is the life expectancy and consequence for very elderly woman with stage 4 kidney disease (17%) who refuse dyliasis treatment?

This would be hard to estimate without a full review of all the information. It would be a good idea to begin discussing the final wishes of the woman directly with her and the family. Have her write out all her thoughts and desires while she still has the mental capacity to do so. This type of failure leads to a decline in mental function before the end.

If you give me the exact patient's age and the cause of kidney disease, not just elderly, I can give you a better prediction. In general, when a patient reaches end stage kidney disease (CKD 5) he or she can survive a maximum of 2 years with conservative treatment and the mean survival will be around 6-12 months. Some CKD cases do not lose kidney function more than 1% per year, just let you know.