A mild decrease of renal function is related to increased hemoglobin level during 5-year follow-up period.
OBJECTIVE
We analyzed chronological changes in hemoglobin according to renal function changes over a 5-year follow-up period.


METHODS
We enrolled 5,266 adults with a glomerular filtration rate (GFR) ≥ 60 mL/min/1.73 m(2) at an initial examination at a routine health check-up; a follow-up examination was conducted 5 years later. We categorized the subjects according to GFR ratio (groups 1, 2, and 3, defined as GFRratio ≥ 1.00, 0.75 to 0.99, and < 0.75, respectively).


RESULTS
The mean hemoglobin level in subjects with a GFR of 60 to 74 was higher than in those with a GFR of 75 to 89 or ≥ 90 mL/min/1.73 m(2) at the initial examination (all p < 0.001). Among females and males, the frequencies of increased hemoglobin were 46.8% and 40.6% in the GFRratio group 1, 52.4% and 46.1% in group 2, and 59.6% and 52.5% in group 3 over the 5-year period, respectively (all p < 0.001). With multiple logistic regression, group 3 showed 1.594-fold (95% confidence interval [CI], 1.127 to 2.225) and 1.353-fold (95% CI, 1.000 to 1.830) higher likelihoods of increased hemoglobin over the 5-year follow-up period in females and males, respectively. The estimated difference in hemoglobin level was highest in group 3 in both genders. These findings were more evident in subgroups without metabolic syndrome, diabetes mellitus, hypertension, or GFR less than 90 mL/min/1.73 m(2).


CONCLUSIONS
Among a population with GFR ≥ 60 mL/min/1.73 m(2), a mild decrease in GFR over a 5-year follow-up period was associated with an increase in hemoglobin levels.
Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea.
Nara
N
Shin
Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea.
Hyunsuk
H
Kim
Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea.
Hyo Jin
HJ
Kim
Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea.
Miyeun
M
Han
Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea.
Sunhwa
S
Lee
Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea.
Hyungah
H
Jo
Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea.
Huh
H
Hyuk
Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Korea. ; Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea. ; Renal Institute, Seoul National University Medical Research Center, Seoul, Korea.
Ho Jun
HJ
Chin
D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D016009:Chi-Square Distribution; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D005919:Glomerular Filtration Rate; D006454:Hemoglobins / Q000378:metabolism*; D006801:Humans; D007668:Kidney / Q000503:physiopathology*; D007674:Kidney Diseases / Q000097:blood / Q000175:diagnosis / Q000503:physiopathology*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D056910:Republic of Korea; D013997:Time Factors; D015854:Up-Regulation
D015415:Biomarkers; D006454:Hemoglobins
Chronic kidney failure; Erythropoiesis; Hemoglobins