An online tool that uses two kidney failure risk equations appears to accurately predict the probability of kidney failure at 2 and 5 years in individuals with chronic kidney disease (CKD) across a wide range of geographic regions and patient populations, researchers report in an article published in the January 12 issue of JAMA.

"This tool allows doctors to sit down with their patients and explain how likely it is that their kidneys will fail in the near future," Josef Coresh, MD, PhD, the George W. Comstock Professor of Epidemiology at the Bloomberg School, and head of the Chronic Kidney Disease Prognosis Consortium, which conducted the study, said in a news release.

"While the tool can aid in management of a patient's disease and prepare them for the worst, many more patients will find the results reassuring. You can reassure a lot of worried people with the fact that their risk is actually very low. The vast majority of patients will not need dialysis," he added.

As previously reported by Medscape Medical News, the tool, which uses four- and eight-variable equations, was initially developed using 3449 patients with stages 3 to 5 CKD in Ontario, Canada, and validated in referred patients with CKD in British Columbia, Canada. The four-variable equation requires age, sex, estimated glomerular filtration rate, and urinary albumin-to-creatinine ratio, whereas the eight-variable equation also requires calcium, phosphate, bicarbonate, and albumin, making it useful when more precision is desired, the study authors explain.

In the current study, Navdeep Tangri, MD, PhD, from the Department of Medicine, Seven Oaks General Hospital, University of Manitoba, Winnipeg, Canada, and colleagues evaluated the tool in a collaborative meta-analysis comprising 721,357 participants with CKD stages 3 to 5 from a total of 31 cohorts (16 based in North American and 15 from Asia, Europe, and Australasia) with an average follow-up of 4.2 years.

The researchers formed new pooled kidney failure risk equations by estimating and combining cohort-specific hazard ratios, using risk factors from the original equations.

"In general, the pooled 4- and 8-variable equations resulted in similar discrimination to the original equations," which were excellent for the 2- and 5-year predicted probability of kidney failure, they report.

"Discrimination of the 8-variable risk equation was slightly better than the 4-variable equation in cohorts that had the necessary components for both equations," the authors explain, noting this to be true using either the original or the pooled risk equations and in nearly all subgroups of interest.

Recalibration was not needed in most North American cohorts; however, a regional calibration factor in non-North American cohorts improved calibration, making the risk equations clinically useful in countries with different levels of baseline risk, they add.

The use of the four-variable equation "is consistent with the Kidney Disease Improving Global Outcomes (KDIGO) guideline, which recommends integration of risk prediction in the evaluation and management of CKD and is in agreement with a strong body of evidence demonstrating the importance of [estimated glomerular filtration rate] and albuminuria in predicting prognosis," Dr Tangri and colleagues write. In addition, it can easily be implemented in electronic medical records and laboratory information systems.

The incremental improvement observed with the eight-variable risk equation "was smaller than in the original study but may be meaningful for patients for whom data for both equations is readily available," the authors state.

"These findings suggest that the 4-variable risk equation might be adopted more widely, but the 8-variable equation should be made available if the additional variables are obtained and increased precision is desired."

The tool is freely available at

Dr Tangri reports financial relationships with Takeda Inc and Otsuka. Study coauthors also disclosed patent applications pending for glomerular filtration rate estimation and relationships with CKD-EPI, Amgen, Merck, Astra Zeneca, ZS Pharma, Hospira, NxStage, Relypsa, Bayer, Astellas, Pharmalink AB, Otsuka, Gilead Sciences, Abbott, NPS, sanofi-aventis, ZS Pharma, AbbVie, OPKO, Shire, Boehringer Ingelheim, and Janssen.

JAMA. 2016;315:164-174. Abstract