Kidney disease measures on mortality, ESRD unaffected by age

Nov 23 2012

By Liam Davenport, medwireNews Reporter

Regardless of age, estimated glomerular filtration rate (eGFR) and high albuminuria are linked to death and end-stage renal disease (ESRD), say US scientists who found a lower relative but higher absolute mortality risk difference at older age.

"Our findings have several important implications," the team writes in the Journal of the American Medical Association. "First, our study shows that the kidney measures used for defining and staging [chronic kidney disease] CKD are strong predictors of clinical risk across the full age range, including age 75 years or older in many cohorts."

They say their data support recommendations that CKD measures should be added to mortality risk equation, adding that "the strong increase in mortality rate along with kidney measures at older ages suggests that older adults should not be left out from management strategies of CKD."

Josef Coresh, from the Chronic Kidney Disease Prognosis Consortium Data Coordinating Center, in Baltimore, Maryland, and colleagues studied data from 33 general population cohorts or cohorts at high-risk for vascular disease and 13 CKD cohorts from North and South America, Asia, Australasia, and Europe. A total of 2,051,244 patients were studied between 1972 and 2011, and followed up for an average of 5.8 years.

Overall, there were 121,352 deaths and 8728 ESRD events. Mortality risks in general and high-risk cohorts were higher at lower eGFR and higher albuminuria for patients aged 18-54 years, 55-64 years, 65-74 years, and 75 years or older.

For example, at an eGFR of 45 versus 80 ml/min per 1.73m², the hazard ratios for mortality were 3.50, 2.21, 1.59, and 1.35, respectively, for the age categories, while the respective absolute risk differences were 9.0, 12.2, 13.3, and 17.2 excess deaths per 1000 person-years.

At an albumin to creatinine ratio of 300 versus 10 mg/g, respective mortality hazard ratios for the age categories were 2.53, 2.30, 2.10, and 1.73. The absolute risk differences were 7.5, 12.2, 22.7, and 34.3 excess deaths per 1000 person-years, respectively.

In CKD cohorts, and for ESRD, there were no significant differences between age groups, and the risks were largely parallel, the researchers conclude.

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