Burden of Chronic Kidney Disease by KDIGO Categories of Glomerular Filtration Rate and Albuminuria: A Systematic Review.

INTRODUCTION: The Kidney Disease: Improving Global Outcomes (KDIGO) 2012 guidelines recommend classifying patients by glomerular filtration rate (GFR) and albuminuria to predict chronic kidney disease (CKD) prognosis. The aim of this systematic review was to explore the epidemiological burden of CKD stratified by the KDIGO 2012 categories. METHODS: MEDLINE® and Embase were searched for observational studies of patients with CKD with results stratified according to the KDIGO 2012 classification. Investigated outcomes were prevalence, incidence, and risk factors and complications of CKD, including mortality. RESULTS: The review included ten observational studies with 3033 to 46,949 participants, conducted in the USA, China, France, Italy and Spain. The most frequently reported outcome was the prevalence of CKD (GFR categories G3-5), ranging from 2% to 17%. Most participants were normoalbuminuric, with 0.4-3.2% macroalbuminuric, and most fell within the KDIGO 2012 low-risk or moderate-risk groups, with 0.9-5.6% in the high-risk and 0.3-4.8% in the very high-risk groups. Although scarce, data on the prevalence of comorbidities in CKD according to the KDIGO classification suggest that they increase with albuminuria severity. CONCLUSIONS: Patients with CKD frequently have complications, but only a small proportion have severely increased albuminuria or fall within the KDIGO high-risk or very high-risk groups. These groups, however, are associated with the highest burden of disease, as comorbidities are more prevalent with increasing albuminuria severity. New studies framed by the KDIGO 2012 classification are needed to address key gaps in the understanding of CKD burden and outcomes