Chronic kidney disease independently increases mortality risk

Oct 4 2012

By Ingrid Grasmo, medwireNews Reporter

Findings from two meta-analyses published in The Lancet show that patients with chronic kidney disease are at high risk for death and end-stage renal disease (ESRD) even if they do not have comorbid hypertension or diabetes.

Although mortality risk was generally increased in patients with hypertension or diabetes, the specific impact of chronic kidney disease on survival was equally strong in patients with and without these comorbidities.

"These data provide support for clinical practice guidelines which stage chronic kidney disease based on kidney function and urine protein across all causes of kidney disease," said lead researcher for both studies Josef Coresh (Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA) in an associated press release.

The first study, which investigated the association of hypertension with death and ESRD, included data from 45 cohorts (25 general population, 13 chronic kidney disease, and seven high-risk) involving 1,127,656 participants, of whom 32.3% had hypertension.

Overall, the risk for all-cause and cardiovascular mortality rose with decreasing estimated glomerular filtration rate (eGFR). But this association was strongest in patients who did not have hypertension. Specifically, each 15 mL/min per 1.73 m² reduction in eGFR was associated with a 5% larger increase in all-cause mortality risk and an 11% greater rise in cardiovascular mortality risk among patients without relative to those with hypertension.

By contrast, the risk for patients progressing to ESRD was similar irrespective of whether they had hypertension.

The second study looked at the effect of diabetes. It included data for 1,024,977 patients (30 general and high-risk cohorts and 13 chronic kidney disease cohorts), of whom 12.5% had diabetes, and showed that in the general and high-risk cohorts, mortality risks were 1.2-1.9-fold higher in patients with diabetes than in those without.

However, at a fixed eGFR of 45 ml/minute per 1.73 m² and a fixed albumin-to-creatinine ratio of 30 mg/g, patients with and without diabetes had similar mortality risks, and they also had similar risks for progression to ESRD.

In an associated editorial, Paul Stevens and Christopher Farmer (East Kent Hospitals University NHS Foundation Trust, Canterbury, UK) comment: "These two studies underline the association of adverse outcomes with moderate reduction in kidney function and low levels of proteinuria, but we still need to know why this association occurs."

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