Time to rethink the current paradigm for assessing kidney function in drug development and beyond.

Chronic kidney disease (CKD) is an important health issue that affects about 9.1% of the world adult population. Serum creatinine is the most commonly used biomarker for assessing kidney function and is utilized in different equations for estimating creatinine clearance (CrCL) or glomerular filtration rate (GFR). Cockcroft-Gault formula for adults and "original" Schwartz formula for children have been the most commonly used equations for estimating kidney function during the last 3-4 decades. Introduction of standardized serum creatinine bioanalytical methodology has reduced inter-laboratory variability but is not intended to be used with Cockcroft-Gault or original Schwartz equations. More accurate equations (for instance, CKD-EPI for adults and bedside Schwartz or CKID Schwartz equation for children) based on standardized serum creatinine values (and another biomarker - Cystatin C) have been introduced and validated in recent years. Recently, CKD-EPI equation refitted without race variable was introduced. Clinical practice guidance in nephrology advocates a shift to these equations for managing healthcare of patients with CKD. The guidance also recommends use of albuminuria in addition to GFR for CKD diagnosis and management. Significant research with large datasets would be necessary to evaluate if this paradigm would also be valuable in drug dose adjustments. This article attempts to highlight some important advancements in the field from a clinical pharmacology perspective and is a call for action to industry, regulators and academia to rethink the current paradigm for assessing kidney function to enable dose recommendation in patients with CKD.