Authors
Rossing P. Hougaard P. Borch-Johnsen K. Parving HH.
Institution
Steno Diabetes Centre, Gentofte, Denmark.
Title
Predictors of mortality in insulin
dependent diabetes: 10 year observational follow up study.
Source
BMJ. 313(7060):779-84, 1996 Sep 28.
Abstract
OBJECTIVE: To evaluate the prognostic significance of microalbuminuria and
overt diabetic nephropathy and other putative risk factors for cardiovascular
and all cause mortality in insulin dependent diabetes.
DESIGN: Ten year observational follow up study. SETTING: Outpatient diabetic
clinic in a tertiary referral centre. SUBJECTS: All 939 adults with insulin
dependent diabetes (duration of diabetes five years or more) attending the
clinic in 1984; 593 had normal urinary albumin excretion (< or = 30 mg/24 h),
181 persistent microalbuminuria (31-299 mg/24 h), and 165 overt nephropathy
(> or = 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 nephropathy at baseline died during follow up. Cox multiple
regression analysis identified the following significant
predictors of all cause mortality: 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), log10 urinary albumin
excretion (1.45; 1.18 to 1.77), hypertension (1.63; 1.18 to 2.25), log10
serum creatinine concentration (8.96; 3.34 to 24.08), and haemoglobin A1c
concentration (1.11; 1.03 to 1.20). Age, smoking, microalbuminuria, overt
nephropathy, and hypertension were significant predictors of
cardiovascular mortality. Mortality in
patients with microalbuminuria was only slightly increased compared with that
in patients with normoalbuminuria. Median survival time after the onset of
overt diabetic nephropathy was 13.9 years (95% confidence interval 11.8 to
17.2 years). CONCLUSIONS: Abnormally increased urinary albumin excretion and
other potentially modifiable risk factors such as hypertension, smoking, poor
glycaemic control, and social class predict increased
mortality in insulin dependent diabetes. Microalbuminuria by
itself confers only a small increase in mortality. The
prognosis of patients with overt diabetic nephropathy has improved, probably
owing to effective antihypertensive treatment.