Canadian society of nephrology commentary on the KDIGO clinical practice guideline for CKD evaluation and management

We congratulate the KDIGO (Kidney Disease: Improving Global Outcomes) work group on their comprehensive work in a broad subject area and agreed with many of the recommendations in their clinical practice guideline on the evaluation and management of chronic kidney disease. We concur with the KDIGO definitions and classification of kidney disease and welcome the addition of albuminuria categories at all levels of glomerular filtration rate (GFR), the terminology of G categories rather than stages to describe level of GFR, the division of former stage 3 into new G categories 3a and 3b, and the addition of the underlying diagnosis. We agree with the use of the heat map to illustrate the relative contributions of low GFR and albuminuria to cardiovascular and renal risk, though we thought that the highest risk category was too broad, including as it does people at disparate levels of risk. We add an albuminuria category A4 for nephrotic-range proteinuria and D and T categories for patients on dialysis or with a functioning renal transplant. We recommend target blood pressure of 140/90 mm Hg regardless of diabetes or proteinuria, and against the combination of angiotensin receptor blockers with angiotensin-converting enzyme inhibitors. We recommend against routine protein restriction. We concur on individualization of hemoglobin A_1c targets. We do not agree with routine restriction of sodium intake to <2 g/d, instead suggesting reduction of sodium intake in those with high intake (>3.3 g/d). We suggest screening for anemia only when GFR is <30 mL/min/1.73 m². We recognize the absence of evidence on appropriate phosphate targets and methods of achieving them and do not agree with suggestions in this area. In drug dosing, we agree with the recommendation of using absolute clearance (ie, milliliters per minute), calculated from the patient's estimated GFR (which is normalized to 1.73 m²) and the patient's actual anthropomorphic body surface area. We agree with referral to a nephrologist when GFR is <30 mL/min/1.73 m² (and for many other scenarios), but suggest urine albumin-creatinine ratio > 60 mg/mmol or proteinuria with protein excretion > 1 g/d as the referral threshold for proteinuria.