1. Current chronic kidney disease (CKD) prognosis equations remain accurate even among non-white ethnicities and in patient populations outside of North America.
2. The main risk factors for progressing to renal failure are younger age, male sex, lower eGFR, and higher levels of albuminuria.
Evidence Rating Level: 1 (Excellent)
Study Rundown: CKD prognosis calculators are currently only validated in white patients under the care of a nephrologist in North America. This study sought to further expand the validation of CKD prognosis calculators to a wider range of patients. In doing so, the study concluded that the current 4- and 8-variable prognostic equations are generalizable to a broad spectrum of patients, including those of non-white ancestry and outside of North America.
Along with the practicality of this study’s central question, strengths of the analysis include the large number of cohorts analyzed and its provision of recalibration factors for specific patient populations. The risk factor results of this study are similar to other prior studies, increasing one’s confidence in the validity of the results. Though this study was limited by analyzing cohorts from only 30 countries and excluding patients with stage I and stage II CKD, it provides confidence in the estimation of CKD prognosis across a variety of individuals.
In-Depth [meta-analysis]: Aiming to assess the validity of current CKD prognosis calculators across varying populations, this systematic review utilized data from the Chronic Kidney Disease Prognosis Consortium collected between 1982 and 2014 in 31 cohort studies conducted across 30 countries. Of note, roughly half of the cohorts were comprised of patients outside of North America. The study included 721,357 patients who did not have kidney failure at baseline and were diagnosed with stage 3-5 CKD. Utilizing currently accepted CKD prognosis calculators, the study sought to validate the risk of developing renal failure, defined as initiation of hemodialysis or kidney transplant, among this broad range of patients. In total, 23,829 events of kidney failure were observed during a mean follow-up time of 4 years. The study then assessed the validity of using the 4-variable prognosis calculator (which includes age, sex, eGFR, and albumin to creatinine ratio) and 8-variable calculator (which adds serum levels of calcium, phosphate, bicarbonate, and albumin) to differentiate between patients who would develop renal failure and those who would not. There was good discrimination within the North American population (C-statistic ranging between 0.82 and 0.94) and non-North American population (C-statistic ranging between 0.77 and 0.96). These results clearly demonstrated the accuracy of both calculators in a wide range of patients. In addition, recalibration factors were determined to provide better discrimination in various subpopulations with differing baseline risks of CKD progression. In terms of the factors that affected prognosis, patients who were younger, male, had a lower eGFR, and a higher level of albuminuria were at a greater risk of developing renal failure.
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