A prospective study of depression and mortality in patients with type 2 diabetes: the Fremantle Diabetes Study.
OBJECTIVE
Depression is associated with excess mortality in patients with type 2 diabetes. We investigated the impact, and possible causal mechanisms, of depression on all-cause and cardiac mortality in patients with type 2 diabetes.


METHODS
We recruited 1,273 patients with type 2 diabetes from a postcode-defined community (average age 64.1+/-11.2 years, 48.7% males, median duration of diabetes 4 years [range 1.0-9.0]) and followed them for 7.8+/-2.4 years. Depression was assessed using data obtained using a quality-of-life questionnaire, and cause and date of death were obtained from the state registry.


RESULTS
Depression was present in 31.5% of subjects at recruitment. Depressed subjects had a longer duration of diabetes, more cardiovascular risk factors, CHD, cerebrovascular disease and diabetic microvascular complications at baseline, and higher all-cause and cardiac mortality rates during follow-up. In Cox proportional hazards models and after adjustment for demographic and diabetes-related variables and cardiovascular risk factors, depression was significantly associated with excess all-cause and cardiac mortality. When diabetic microvascular and macrovascular complications were added to the Cox models, depression was not significantly associated with excess all-cause or cardiac mortality.


CONCLUSIONS
Depression in patients with type 2 diabetes is associated with a greater prevalence of complications but is not an independent predictor of all-cause or cardiac mortality. Depression may contribute to the progression of important prognostic variables in diabetes, particularly macrovascular and microvascular disease.
Bruce
D G
DG
School of Medicine and Pharmacology, University of Western Australia, Perth, WA, Australia. dbruce@cyllene.uwa.edu.au
Davis
W A
WA
Starkstein
S E
SE
Davis
T M E
TM
D000368:Aged; D002318:Cardiovascular Diseases / Q000150:complications / Q000453:epidemiology / Q000401:mortality; D015984:Causality; D015331:Cohort Studies; D003627:Data Interpretation, Statistical; D003863:Depression / Q000150:complications* / Q000453:epidemiology* / Q000523:psychology; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology / Q000401:mortality* / Q000523:psychology*; D003925:Diabetic Angiopathies / Q000150:complications / Q000453:epidemiology* / Q000401:mortality*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D011788:Quality of Life / Q000523:psychology; D015203:Reproducibility of Results; D012307:Risk Factors; D011795:Surveys and Questionnaires; D013997:Time Factors; D014904:Western Australia / Q000453:epidemiology