P. Rossing et al., PREDICTORS OF MORTALITY IN INSULIN-DEPENDENT DIABETES - 10-YEAR OBSERVATIONAL FOLLOW-UP-STUDY, BMJ. British medical journal, 313(7060), 1996, pp. 779-784
Objective-To evaluate the prognostic significance of microalbuminuria
and overt diabetic nephropathy and other putative risk factors for car
diovascular and all cause mortality in insulin dependent diabetes. Des
ign-Ten year observational follow up study. Setting-Outpatient diabeti
c clinic in a tertiary referral centre. Subjects-All 939 adults with i
nsulin dependent diabetes (duration of diabetes five years or more) at
tending the clinic in 1984; 593 had normal urinary albumin excretion (
less than or equal to 30 mg/24 h), 181 persistent microalbuminuria (31
-299 mg/24 h), and 165 overt nephropathy (greater than or equal to 300
mg/24 h). Main outcome measure-All cause and cardiovascular mortality
. Results-Fifteen per cent of patients (90/593) with normoalbuminuria,
25% (45/181) with microalbuminuria, and 44% (72/165) with overt nephr
opathy at baseline died during follow up. Cox multiple regression anal
ysis identified the following significant predictors of all cause mort
ality: male sex (relative risk 2.03; 95% confidence interval 1.37 to 3
.02), age (1.07; 1.06 to 1.08), height (0.96; 0.94 to 0.98), smoking (
1.51; 1.09 to 2.08), social class V versus social class IV (1.70; 1.25
to 2.31), log(10) urinary albumin excretion (1.45; 1.18 to 1.77), hyp
ertension (1.63; 1.18 to 2.25), log(10) serum creatinine concentration
(8.96; 3.34 to 24.08), and haemoglobin A(1c) concentration (1.11; 1.0
3 to 1.20). Age, smoking, microalbuminuria, overt nephropathy, and hyp
ertension were significant predictors of cardiovascular mortality. Mor
tality in patients with microalbuminuria was only slightly increased c
ompared with that in patients with normoalbuminuria. Median survival t
ime after the onset of overt diabetic nephropathy was 13.9 years (95%
confidence interval 11.8 to 17.2 years). Conclusions-Abnormally increa
sed urinary albumin excretion and other potentially modifiable risk fa
ctors such as hypertension, smoking, poor glycaemic control, and socia
l class predict increased mortality in insulin dependent diabetes. Mic
roalbuminuria by itself confers only a small increase in mortality. Th
e prognosis of patients with overt diabetic nephropathy has improved,
probably owing to effective antihypertensive treatment.