Absolute level and rate of change of albuminuria over 1 year independently predict mortality and cardiovascular events in patients with diabetic nephropathy.
OBJECTIVE
To determine the nature of the association between baseline albuminuria and risk of all-cause mortality and cardiovascular disease, and to determine if the rate of change of albuminuria from baseline over 1 year predicts these endpoints in patients with diabetic nephropathy.


METHODS
Cohort study of 427 patients (161 Type 1 and 266 Type 2) with diabetic nephropathy defined as urinary albumin excretion (UAE) > or = 30 mg/24 h at baseline (mean age 53.4 years). Patients were recruited at the time of referral to a diabetic nephropathy clinic and followed up annually for an average of 5 years. UAE rate was re-measured at 1 year and the rate of change from baseline calculated.


RESULTS
All-cause mortality and cardiovascular disease increased significantly and continuously across quintiles of baseline UAE (P for linear trend < 0.001 in both outcomes). The rate of change of albuminuria over 1 year (log10) independently predicted all-cause mortality (hazard ratio (95% confidence interval) 1.76 (1.39, 3.11)) and cardiovascular mortality (1.57 (1.13, 5.22)). Taken as a categorical variable, a rate of change of albuminuria > or = 30% independently predicted mortality and cardiovascular events (2.07 (1.5, 4.30) and 1.89 (1.33, 4.06), respectively).


CONCLUSIONS
The rate of change of albuminuria over 1 year independently predicts mortality and cardiovascular disease in diabetic nephropathy and may have clinical utility as a risk marker in identifying a subgroup of patients at particular risk. The risk of these outcomes is continuous across the range of baseline albuminuria in patients with diabetic nephropathy.
Yuyun
M F
MF
Department of Medicine, School of Clinical Medicine, University of Cambridge, Cambridge, UK.
Dinneen
S F
SF
Edwards
O M
OM
Wood
E
E
Wareham
N J
NJ
D000328:Adult; D000419:Albuminuria / Q000209:etiology*; D002318:Cardiovascular Diseases / Q000150:complications*; D015331:Cohort Studies; D003929:Diabetic Neuropathies / Q000150:complications* / Q000401:mortality / Q000652:urine; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests