TY - JOUR
T1 - Predictivity of survival according to different equations for estimating renal function in community-dwelling elderly subjects
AU - Pizzarelli, Francesco
AU - Lauretani, Fulvio
AU - Bandinelli, Stefania
AU - Windham, Gwen B.
AU - Corsi, Anna Maria
AU - Giannelli, Sandra V.
AU - Ferrucci, Luigi
AU - Guralnik, Jack M.
PY - 2009/4
Y1 - 2009/4
N2 - Background. Detection of subjects with early chronic kidney disease (CKD) is important because some will progress up to stage 5 CKD, and most are at high risk of cardiovascular morbidity and mortality. While validity and precision of estimated glomerular filtration rate (eGFR) equations in tracking true GFR have been repeatedly investigated, their prognostic performance for mortality has not been hitherto compared. This is especially relevant in an elderly population in whom the risk of death is far more common than progression. Methods. We analysed data of participants in the InCHIANTI study, a community-based cohort study of older adults. Twenty-four-hour creatinine clearance (Ccr), CockcroftGault (C-G) and Modification of Diet in Renal Disease (MDRD)-derived equations (six and four input variables) were calculated at enrolment (19982000), and all-cause mortality and cardiovascular mortality were prospectively ascertained by Cox regression over a 6-year follow-up. Results. Of the 1270 participants, 942 (mean age 75 years) had complete data for this study. The mean renal function ranged from 77 ml/min/1.73 m2 by Ccr to 64 ml/min/1.73 m2 by C-G. Comparisons among equations using K/DOQI staging highlight relevant mismatches, with a prevalence of CKD ranging from 22% (MDRD-4) to 40% (C-G). Reduced renal function was a strong independent predictor of death. In a Cox modeladjusted for demographics, physical activity, comorbidities, proteinuria and inflammatory parametersparticipants with Ccr 6090 ml/min/1.73 m2 and Ccr 90 ml/min/1.73 m2. For the C-G, the group with val-ues 90 ml/min/1.73 m2 (HR 2.59, 95% CI: 1.135.91). The classification based on the MDRD formulae did not provide any significant prognostic information. The adjusted risk of all-cause mortality followed a similar pattern when Ccr and estimating equations were introduced as continuous variables or dichotomized as higher or lower than 60 ml/min. C-G was the best prognostic indicator of cardiovascular mortality. Possibly, Ccr and C-G are better prognostic indicators than MDRD-derived equations because they incorporate a stronger effect of age. Conclusions. In a South-European elderly population, the prevalence of CKD is high and varies widely according to the method adopted to estimate GFR. Researchers and clinicians who want to capture the prognostic information on mortality related to kidney function should use the Ccr or C-G formula and not MDRD equations. These results highlight the importance of strategies for early detection and clinical management of CKD in elderly subjects.
AB - Background. Detection of subjects with early chronic kidney disease (CKD) is important because some will progress up to stage 5 CKD, and most are at high risk of cardiovascular morbidity and mortality. While validity and precision of estimated glomerular filtration rate (eGFR) equations in tracking true GFR have been repeatedly investigated, their prognostic performance for mortality has not been hitherto compared. This is especially relevant in an elderly population in whom the risk of death is far more common than progression. Methods. We analysed data of participants in the InCHIANTI study, a community-based cohort study of older adults. Twenty-four-hour creatinine clearance (Ccr), CockcroftGault (C-G) and Modification of Diet in Renal Disease (MDRD)-derived equations (six and four input variables) were calculated at enrolment (19982000), and all-cause mortality and cardiovascular mortality were prospectively ascertained by Cox regression over a 6-year follow-up. Results. Of the 1270 participants, 942 (mean age 75 years) had complete data for this study. The mean renal function ranged from 77 ml/min/1.73 m2 by Ccr to 64 ml/min/1.73 m2 by C-G. Comparisons among equations using K/DOQI staging highlight relevant mismatches, with a prevalence of CKD ranging from 22% (MDRD-4) to 40% (C-G). Reduced renal function was a strong independent predictor of death. In a Cox modeladjusted for demographics, physical activity, comorbidities, proteinuria and inflammatory parametersparticipants with Ccr 6090 ml/min/1.73 m2 and Ccr 90 ml/min/1.73 m2. For the C-G, the group with val-ues 90 ml/min/1.73 m2 (HR 2.59, 95% CI: 1.135.91). The classification based on the MDRD formulae did not provide any significant prognostic information. The adjusted risk of all-cause mortality followed a similar pattern when Ccr and estimating equations were introduced as continuous variables or dichotomized as higher or lower than 60 ml/min. C-G was the best prognostic indicator of cardiovascular mortality. Possibly, Ccr and C-G are better prognostic indicators than MDRD-derived equations because they incorporate a stronger effect of age. Conclusions. In a South-European elderly population, the prevalence of CKD is high and varies widely according to the method adopted to estimate GFR. Researchers and clinicians who want to capture the prognostic information on mortality related to kidney function should use the Ccr or C-G formula and not MDRD equations. These results highlight the importance of strategies for early detection and clinical management of CKD in elderly subjects.
KW - CockcroftGault formula
KW - Elderly
KW - MDRD equations
KW - Mortality
KW - Population-based study
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U2 - 10.1093/ndt/gfn594
DO - 10.1093/ndt/gfn594
M3 - Article
C2 - 18988669
AN - SCOPUS:65349100186
VL - 24
SP - 1197
EP - 1205
JO - Proceedings of the European Dialysis and Transplant Association - European Renal Association. European Dialysis and Transplant Association - European Renal Association. Congress
JF - Proceedings of the European Dialysis and Transplant Association - European Renal Association. European Dialysis and Transplant Association - European Renal Association. Congress
SN - 0931-0509
IS - 4
ER -