Elevated relative mortality risk with mild-to-moderate chronic kidney disease decreases with age.
Renal disease is common in the general population and whilst few people progress to end-stage renal failure, mortality is increased. The aim of this study was to examine all-cause mortality risk in relation to chronic kidney disease (CKD) stages defined by estimated glomerular filtration rate (eGFR).



Data were extracted from a computerized central laboratory system for a defined geographical area over a 3-year study period. The eGFR was calculated using the four-variable Modification of Diet in Renal Disease (MDRD) formula and aligned to the MDRD laboratory. Average annual mortality and relative risk (RR) of all-cause mortality was determined and compared for defined age and CKD bands.



106 366 participants (55.5% female; 85% White, 13% South Asian, 2% Black and others) were eligible and studied, representing 49% of the Coventry adult population. 12 540 (12%) of the sample had some evidence of decreased kidney function, with an eGFR <60 ml/min/1.73 m2. 7611 (7%) participants died and there were significantly elevated risks of mortality with increasing renal dysfunction; RR = 4.0, 8.3, 16.2 and 43.5 for eGFR 45-59, 30-44, 15-29 and <15 ml/min/1.73 m2, respectively. Within age bands, RRs were statistically significantly raised with CKD progression and within CKD stage, RR of death decreased as age increased.



CKD prevalence increased with age and absolute and RR of mortality increased with progression of CKD. People aged over 75 years, with mild-to-moderate renal disease, representing 41% of this age group, have no increased RR of mortality. Further study of CKD and mortality, particularly progression over time and with respect to age is needed.
Raymond
Neil T
NT
Health Sciences Research Institute, Warwick Medical School, University of Warwick, Coventry, CV4 7AL, UK.
Zehnder
Daniel
D
Smith
Stephen C H
SC
Stinson
Julie A
JA
Lehnert
Hendrik
H
Higgins
Robert M
RM
D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D044466:Asian People / Q000208:ethnology; D003928:Diabetic Nephropathies / Q000401:mortality; D018450:Disease Progression; D004739:England; D006801:Humans; D007676:Kidney Failure, Chronic / Q000401:mortality*; D008875:Middle Aged; D015996:Survival Rate; D044465:White People