CKD and mortality risk in older people: a community-based population study in the United Kingdom

Abstract

Background: the prevalence of chronic kidney disease (CKD) increases with age; however, the
prognostic significance in older people is uncertain. This study aims to determine the association of CKD
with all-cause and cardiovascular mortality in community-dwelling older people 75 years and older.
Study Design: Cohort study of people 75 years and older recruited in 1994 to 1999 to 1 arm of a trial
of multidimensional health assessment with mortality follow-up.
Setting & Participants: 53 general practices in Great Britain. 15,336 (73%) of those eligible
participated. 13,177 (86%) had serum creatinine measured at baseline.

Main Factor: estimated glomerular filtration rate (eGFR).
Outcomes: All-cause and cardiovascular mortality.
Measurements: eGFR derived from serum creatinine level using the 4-variable Modification of Diet in
Renal Disease (MDRD) Study equation in milliliters per minute per 1.73 m2; dipstick proteinuria.
Mortality by linkage to national death registration and death certification.

Results: after a median follow-up of 7.3 years (interquartile range, 5.0), 7,633 (58%) had died, 42% of
cardiovascular causes. In the first 2 years of follow-up, adjusted hazard ratios for all-cause mortality in
eGFR bands of 45 to 59, 30 to 44, and less than 30 compared with eGFR greater than 60 mL/min/1.73
m2 were 1.13 (95% confidence interval, 0.93 to 1.37), 1.69 (95% confidence interval, 1.26 to 2.28), and
3.87 (95% confidence interval, 2.78 to 5.38) in men and 1.14 (95% confidence interval, 0.93 to 1.40),
1.33 (95% confidence interval, 1.06 to 1.68), and 2.44 (95% confidence interval, 1.68 to 3.56) in women,
respectively. Hazard ratios were greater for cardiovascular mortality and lower after 2 years. Dipstick
proteinuria was independently associated with all-cause, but not cardiovascular, mortality risk in both
sexes.

Limitations: single serum creatinine measurement, no calibration of serum creatinine, MDRD Study
equation not validated in older people.
Conclusion: As kidney function decreases, there is a graded and independent increase in all-cause
and cardiovascular mortality risk in older people 75 years and older, especially in men and those with
eGFR less than 45 mL/min/1.73 m2. Dipstick proteinuria did not add to cardiovascular mortality risk in
this elderly population. In older people, identification and management of CKD should prioritize the
smaller numbers with more severe CKD.

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Identifiers

ORCID for Paul J. Roderick: orcid.org/0000-0001-9475-6850

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