Biological variability at the patient level.
Fact is, there is too much fluctuation present when using eGFR and UACR as the core measurements for kidney disease progression. For these to be reliable metrics to ascertain kidney disease staging, the patient results would need to be consistent from week to week. Studies indicate that this is not the case.
Hyperfiltration plays a critical role in chronic kidney disease in diabetes as it puts stress on the filtration barrier and post-filtration mechanisms.