Context: Older patients with coronary artery disease often experience depressive symptoms and are vulnerable to developing cognitive impairment. Whether depressive symptoms increase their risk of cognitive decline is unknown.
Objectives: To examine the association between the stability of depressive symptoms and cognitive decline for 30 months among patients undergoing coronary angiography and to explore whether any observed associations were modified by the presence of the apolipoprotein E (APOE) ε4 allele.
Design: Cohort study.
Setting: Urban tertiary care hospital serving southern Alberta.
Participants: Three hundred fifty patients 60 years or older (73.7% male) undergoing nonemergent catheterization (October 27, 2003, through February 28, 2007) without prior revascularization. We compared a baseline measure of depressive symptoms (Geriatric Depression Scale score ≥5) with a dynamic measure capturing change from baseline to 12 months.
Main outcome measures: Mean change in domain (z scores for attention/executive function, learning/memory, and verbal fluency) and global (raw Mini-Mental State Examination) cognitive scores from baseline to 6, 12, and 30 months and from 12 to 30 months.
Results: In adjusted models, participants with persistent depressive symptoms (at baseline and ≥1follow-up visit) showed significantly greater declines at 30 months in attention/executive function (mean z score change, -0.22), learning/memory (-0.19), verbal fluency (-0.18), and global cognition (mean Mini-Mental State Examination [MMSE] score change, -0.99) compared with participants with no or baseline-only depressive symptoms. Persistent depressive symptoms were associated with significantly greater declines in all cognitive measures from 12 to 30 months after adjusting for sociodemographic and clinical factors. For global cognition, a significantly greater decline was evident for patients with persistent depressive symptoms and the APOE ε4 allele (mean MMSE score change, -2.93 [95% CI, -4.40 to -1.45]).
Conclusions: Depressive symptoms persist in some patients with coronary artery disease, placing them at a greater risk for cognitive decline. Whether this decline is additionally modified by the presence of APOE ε4 requires further investigation.