Microalbuminuria and all-cause mortality in 2,089 apparently healthy individuals: a 4.4-year follow-up study. The Nord-Trøndelag Health Study (HUNT), Norway.
BACKGROUND
To date, there are few large follow-up studies of apparently healthy subjects with microalbuminuria (MA). The aim of this study is to examine the association between MA and all-cause mortality in nondiabetic nonhypertensive individuals.


METHODS
We conducted a 4.4-year mortality follow-up of 2,089 men and women (> or =20 years) without diabetes and treated hypertension, randomly selected from the population-based Nord-Trøndelag Health Study (1995 to 1997; n = 65,258). Main outcome measures were adjusted relative risk (RR) for all-cause mortality according to increasing albuminuria, defined at different albumin-creatinine ratio (ACR) levels and in 1/2 or 3 urine samples. The main analysis was performed after exclusion of those with cardiovascular disease.


RESULTS
There was a positive association between all-cause mortality and MA. The lowest ACR level associated with increased RR for mortality was the 60th percentile (> or =6.7 microg/mg [0.76 mg/mmol]; RR, 2.4; 95% confidence interval, 1.1 to 5.2), applying 3 urine samples with an ACR greater than the cutoff level. We found a positive association between mortality and increasing numbers of urine samples with an ACR greater than different cutoff levels, in which 3 urine samples were superior. Results persisted after adjusting for several confounders and excluding individuals with untreated hypertension (systolic blood pressure > or = 140 mm Hg/diastolic blood pressure > or = 90 mm Hg) and those who died during the first year of follow-up.


CONCLUSIONS
Although this study confirms the association of all-cause mortality and ACR level in apparently healthy individuals, intervention trials are necessary before clinical cutoff levels of ACR are established and before screening programs are recommended.
Romundstad
Solfrid
S
HUNT Research Center, Department of Public Health and General Practice, Norwegian University of Science and Technology, Verdal, Norway. solfrid.romundstad@medisin.ntnu.no
Holmen
Jostein
J
Kvenild
Kurt
K
Hallan
Hans
H
Ellekjaer
Hanne
H
D000328:Adult; D000368:Aged; D000419:Albuminuria / Q000453:epidemiology*; D001786:Blood Glucose / Q000032:analysis; D015992:Body Mass Index; D003404:Creatinine / Q000097:blood; D004552:Elder Abuse; D005260:Female; D005500:Follow-Up Studies; D006306:Health Surveys; D006801:Humans; D008055:Lipids / Q000097:blood; D008297:Male; D008875:Middle Aged; D009026:Mortality; D009664:Norway / Q000453:epidemiology; D016016:Proportional Hazards Models; D012306:Risk; D012907:Smoking / Q000453:epidemiology
D001786:Blood Glucose; D008055:Lipids; D003404:Creatinine