I guess at this point in time, eGFR (renal function) is a more established biologically important readout. Alkaline phosphatase is only just beginning to be appreciated as a risk factor for increased vascular calcification and possible cardiovascular events. However, at this point in time my understanding is that alkaline phosphatase enzyme levels have only been clinically associated with these outcomes and not yet proven to be causative. This perspective could change over time.
BDAZ