Lower hemoglobin concentrations and subsequent decline in kidney function in an apparently healthy population aged 60 year and older.
BACKGROUND
Anemia and decreased kidney function are recognized as risk factors for morbidity and mortality in the elderly. The role of hemoglobin in renal function changes among elderly patients is not fully understood.


METHODS
Of 1,500 people screened, 121 normotensive non-diabetic elderly patients were recruited, and underwent biochemistry examinations at the baseline, second and fourth years of a 4-year longitudinal study. Serum creatinine and calculated renal parameters, including the Cockroft-Gault (CG) formula, Modification of Diet in Renal Disease (MDRD) Study and abbreviated MDRD (abMDRD) equations were used to evaluate renal function and progression of kidney disease. Chronic kidney disease (CKD) was defined as a glomerular filtration rate (GFR) of <60 ml/min/1.73 m(2). Multivariate regression analyses were used to explore predictors for decline in renal parameters.


RESULTS
Ages ranged from 60 to 81 year (mean: 71.8+/-3.8). Baseline hemoglobin concentrations ranged from 11.9 to 17.3 g/dl (mean: 14.1+/-1.1). Serum creatinine increased and CG creatinine clearance (CrCl), MDRD and abMDRD GFR decreased during follow-up (all p< or =0.001). The prevalence of CKD significantly increased only in those with baseline hemoglobin concentrations of <14 g/dl (p< or =0.03, based on findings of both MDRD and abMDRD GFR). Baseline hemoglobin correlates with 4-year changes of MDRD and abMDRD GFR in univariate (both p<0.001) and multivariate regression analyses (both p<0.05).


CONCLUSIONS
This longitudinal study revealed that the aging process was associated with decline of renal function in the elderly. Because hemoglobin concentrations are an independent predictor for subsequent decline in kidney function, it should be considered in the assessment of renal disease and GFR in the elderly.
Lee
Ya-Ting
YT
Division of Nephrology, Department of Pediatric, Kaohsiung Medical University Hospital, Taiwan, ROC.
Chiu
Herng-Chia
HC
Su
Ho-Ming
HM
Yang
Jeng-Fu
JF
Voon
Wen-Chol
WC
Lin
Tsung-Hsien
TH
Lai
Wen-Ter
WT
Sheu
Sheng-Hsiung
SH
D000368:Aged; D000369:Aged, 80 and over; D006454:Hemoglobins / Q000032:analysis*; D006801:Humans; D007668:Kidney / Q000502:physiology*; D007677:Kidney Function Tests; D008137:Longitudinal Studies; D008875:Middle Aged; D015999:Multivariate Analysis
D006454:Hemoglobins