Understanding Risks Associated with Chronic Kidney Disease: Translating Observational Data to Patient Care

Chronic kidney disease (CKD),3 which is defined by the estimated glomerular filtration rate (eGFR) and/or albuminuria, is projected to affect approximately 10% to 16% of adults worldwide. Over the past 2 decades, there has been growing appreciation of the increased risk of mortality and adverse clinical outcomes in individuals with a decreased eGFR, compared with those with normal renal function. Cardiovascular disease (CVD) occurs prematurely among patients with CKD. The prevalence is several-fold higher than in the general population, and CVD contributes substantially to increased mortality. Traditional CVD risk factors are more common in these patients, but conventional models (e.g., the Framingham predictive instrument) consistently underestimate risk of future CVD events. A scientific statement by the American Heart Association in 2003 endorsed the position that patients with CKD [eGFR <60 mL · min−1 · (1.73 m2)−1 or microalbuminuria] should be grouped with those at the highest risk for cardiovascular events (coronary risk equivalent); however, the increased CVD risk is neither well recognized nor integrated by the general medical community into the care of individual patients with decreased eGFR or albuminuria.A new clinical practice guideline from the Kidney Disease: Improving Global Outcomes (KDIGO) group recommends altering the classification schema of CKD (Fig. 1A) (1). The new classification reflects an increasing recognition by nephrologists and cardiologists that urinary albumin excretion [defined by an albumin–creatinine ratio (ACR) >10 mg/g] is independently associated in a stepwise fashion with increased rates of all-cause and cardiovascular mortality. This risk appears to increase synergistically in concert with reduction in eGFR [<60 mL · min−1 · (1.73 m2)−1]. The new system, known as CGA, leaves intact the familiar eGFR (G in CGA) categories on which the prior system was focused and adds 2 dimensions: cause (C) …