Few patients with mild chronic kidney disease are at risk for end-stage disease

The vast majority of patients with mild chronic kidney disease (CKD) managed by primary care doctors have a benign disease with little risk of progression and complications, according to a five-year study that followed more than 1,700 patients published in PLOS Medicine by Adam Shardlow from Royal Derby Hospital, UK, and colleagues.

CKD affects 10 to 20 percent of adults in most countries and can progress to end-stage kidney disease, requiring dialysis or kidney transplantation. Previous studies on the progression of the disease have been conducted in large teaching hospitals by kidney specialists, where the most complicated and severe cases are generally referred, despite the fact that most CKD patients have a mild disease and are seen only by primary care doctors. To understand the course of disease in the larger patient population seen in primary care, Shardlow and colleagues recruited 1,741 patients with stage 3 CKD - a mild form of the disease - from 32 primary care practices in Derbyshire, UK. They used the standard Kidney Disease Improving Global Outcomes (KDIGO) criteria to gauge the status of each person's disease at baseline, one year later, and five years later.

After five years, 247 patients (14.2%) had died, mostly of cardiovascular causes; 4 patients (0.2%) had progressed to end-stage disease; 308 others (17.7%) had progressed to a lesser extent; 593 (34.1%) still had stable, stage 3 CKD; and 336 (19.3%) met the criteria for complete remission of CKD. The results also indicated that a handful of factors - including estimated glomerular filtration rate and albuminuria - were associated with CKD progression or remission. The statistics on how patients progress may not be applicable to all populations since the study population was predominantly elderly and white. But in light of the new analysis, "management of CKD in primary care should focus principally on identifying the minority of people at high risk of adverse outcomes," the authors say.

In an accompanying Perspective, Giuseppe Remuzzi and Richard Glassock discuss the evolution of classification and diagnosis of CKD and the challenges of pinpointing surveillance factors that can predict which patients are at risk of their CKD progressing. The new study, they say, "identifies factors, easily obtained and possibly modifiable, that should heighten surveillance for the minority of subjects with CKD Stage 3 who are at risk for progression."

The RRID study is currently funded by a Research Project Grant (R302/0713) from the Dunhill Medical Trust (http://www.dunhillmedical.org.uk). Previous study funding includes a joint British Renal Society (http://www.britishrenal.org) and Kidney Research UK (http://www.kidneyresearchuk.org) fellowship (BRS3/2008, to NJM), and an unrestricted educational grant (EPWE124712-G) from Roche Products Ltd. (https://www.roche.co.uk). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

MWT is a member of the PLOS Medicine editorial board.

Article: Chronic Kidney Disease in Primary Care: Outcomes after Five Years in a Prospective Cohort Stud, Shardlow A, McIntyre NJ, Fluck RJ, McIntyre CW, Taal MW, PLOS Medicine, doi:10.1371/journal.pmed.1002128, published 20 September 2016.