Research News

Low eGFR and high albuminuria predict end stage kidney disease and death at all ages

BMJ 2012; 345 doi: http://dx.doi.org/10.1136/bmj.e7478 (Published 07 November 2012) Cite this as: BMJ 2012;345:e7478

It has been proposed that low estimated glomerular filtration rate (eGFR) and albuminuria in older people may be signs of ageing rather than disease worth treating. The literature is equivocal on this, in part because analytical approaches differ across studies. A consortium conducted a meta-analysis of individual patient data for more than 2 million people to help achieve consensus and aid the implementation of the recently revised classification of chronic kidney disease.

Data from 33 cohort studies done in the general population or people at high risk were included, as well as 13 cohort studies of people with chronic kidney disease. The studies spanned four continents and ages 18-108 years, and were carried out over four decades. Patients were followed up for up to 31 years (mean 5.8 years).

Overall, low glomerular filtration rates and high albuminuria were associated with an increased risk of dying and of end stage kidney disease, regardless of age.

In people without chronic kidney disease, the relative risk of dying with impaired eGFR decreased with age, but the absolute risk increased. For example, if eGFR of 45 mL/min/1.73 m2 was compared with that of 80 mL/min/1.73 m2, adjusted hazard ratios for age categories 8-54, 55-64, 65-74, and 75 years or more were 3.50, 2.21, 1.59, and 1.35, respectively. Absolute risk differences for these comparisons, however, were higher at older age: 9.0, 12.2, 13.3, and 27.2 excess deaths per 1000 person years, respectively.

In people with chronic kidney disease, age didn’t modify the association between markers of kidney function and death.

A linked editorial says that we therefore need to diagnose and treat chronic kidney disease in elderly people (doi:10.1001/jama.2012.30761), although the best way to do this is not entirely clear. We need new treatments, as well as testing of existing treatments in this population, which is likely to be most susceptible to the adverse effects of many drugs.

Notes

Cite this as: BMJ 2012;345:e7478