A 12-year follow-up study of all-cause and cardiovascular mortality among 10,532 people newly diagnosed with Type 2 diabetes in Tayside, Scotland.
OBJECTIVE
To determine absolute and relative risks of all-cause and cardiovascular mortality among patients newly diagnosed with Type 2 diabetes.


METHODS
In an observational cohort study using record-linkage databases, based in Tayside, Scotland, UK, we identified newly diagnosed patients with Type 2 diabetes in 1993-2004. We also identified a set of non-diabetic comparators from lists of patients registered with a general practice, individually matched to the diabetic patients by sex, age and deprivation. We followed up patients for mortality and cardiovascular mortality over a 12-year period and calculated hazard ratios using Cox regression.


RESULTS
There were 10,532 patients with Type 2 diabetes and 21,056 non-diabetic comparators. Diabetic patients in every age/sex group had higher absolute mortality rates. Even taking deprivation into account, the hazard ratio for mortality was 1.32 (95% CI 1.25-1.40), decreasing to 1.15 (1.09-1.22) after adjusting for pre-existing cardiovascular disease. The hazard ratios for cardiovascular mortality were higher, decreasing from 1.51 (1.37-1.67) to 1.23 (1.11-1.36) after adjusting for pre-existing cardiovascular disease. The hazard ratios decreased with increasing age at diagnosis, although the difference in absolute rate of mortality increased slightly with age. Increased mortality risks were only evident 2 years after diagnosis and increased thereafter.


CONCLUSIONS
Patients with Type 2 diabetes have an increased risk of all-cause and cardiovascular mortality compared with non-diabetic comparators, although this is not observable immediately after diagnosis. Age at diagnosis and duration of the disease independently affect absolute and relative mortality risk.
Barnett
K N
KN
Division of Clinical and Population Sciences and Education, University of Dundee, UK.
Ogston
S A
SA
McMurdo
M E T
ME
Morris
A D
AD
Evans
J M M
JM
D000328:Adult; D000368:Aged; D002318:Cardiovascular Diseases / Q000175:diagnosis / Q000401:mortality*; D002423:Cause of Death; D015331:Cohort Studies; D016208:Databases, Factual; D003924:Diabetes Mellitus, Type 2 / Q000175:diagnosis / Q000401:mortality*; D003925:Diabetic Angiopathies / Q000175:diagnosis / Q000401:mortality*; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008498:Medical Record Linkage; D008875:Middle Aged; D012307:Risk Factors; D012606:Scotland / Q000453:epidemiology