Diabetes Care, Vol 22, Issue 7 1176-1180, Copyright © 1999 by American Diabetes Association
Increased urinary transferrin excretion predicts microalbuminuria in patients with type 2 diabetes
T Kazumi, T Hozumi, Y Ishida, Y Ikeda, K Kishi, M Hayakawa and G Yoshino
Department of Medicine, Hyogo Rehabilitation Center Hospital, Kobe, Japan.
OBJECTIVE: We studied whether increased urinary transferrin excretion rates
(TERs) (urinary transferrin-to-urinary creatinine ratio > or = 107
micrograms/mmol, which is the sum of an average and 2 SDs in 431 healthy
nondiabetic individuals) would predict the development of microalbuminuria
(urinary albumin-to-urinary creatinine ratio > or = 2.8 mg/mmol) in
patients with type 2 diabetes and normal urinary albumin excretion rates
(AERs) (albumin-to-creatinine ratio < 2.8 mg/mmol). We also studied the
influence of blood pressure, glycemic control, and serum levels of lipids
and apolipoproteins on the later development of microalbuminuria. RESEARCH
DESIGN AND METHODS: In 77 diabetic patients with normal AER, AER and TER
were measured at baseline and after 24 months of follow-up. Blood pressure,
glycemic control, and serum levels of lipids and apolipoproteins were
measured at 1- to 2-month intervals during the follow-up period. RESULTS:
Of the 16 patients who initially had increased TER, 5 (31%) developed
microalbuminuria. In contrast, of the 61 who initially had normal TER, 4
(7%) developed microalbuminuria (P = 0.016). At baseline, no difference was
found in age, sex, diabetes duration, diabetic medications, prevalence of
hypertension, blood pressure, HbA1c levels, or serum lipid and
apolipoprotein concentrations between the two group of patients with normal
and increased TER. There was also no difference in duration of hypertension
and prevalence of users of ACE inhibitors between two subgroups of
hypertensive patients with normal and increased TER. During the 24 month
follow-up period, those whose condition progressed to microalbuminuria had
increased serum levels of triglycerides (1.87 +/- 0.49 vs. 1.29 +/- 0.64
mmol/l, P = 0.003) and apolipoprotein B (114 +/- 20 vs. 102 +/- 24 mg/dl, P
= 0.05) and tended to have increased HbA1c levels (7.7 +/- 1.0 vs. 7.1 +/-
1.1%, P = 0.10) compared with those in whom microalbuminuria did not
develop. Blood pressure, however, did not differ. In multivariate stepwise
logistic regression analysis, the association between increased TER at
baseline and subsequent development of microalbuminuria was significant
(odds ratio 7.04 [95% CI 1.02-48.5], P = 0.04). CONCLUSIONS: In patients
with type 2 diabetes and normal AER, increased TER may predict the
development of microalbuminuria and abnormalities in triglyceride-rich
lipoprotein metabolism, and poor glycemic control may be associated with
this progression.