Untangling causality in nephrology: the example of CKD-MBD and disease progression.

This commentary highlights the innovative use of the g-formula in the European QUALity (EQUAL) study to untangle the causal relationship between chronic kidney disease-mineral and bone disorder biomarkers and kidney disease progression. By addressing time-varying confounding, informative censoring, and competing risks, this approach moves beyond traditional association studies. However, as an observational study, it remains limited by the data collected. The next step is to demonstrate that lowering serum phosphate can effectively slow chronic kidney disease progression.