July 3, 2011American Journal of Psychiatry191 citationsOpen Access
Depressive Symptoms, Health Behaviors, and Subsequent Inflammation in Patients With Coronary Heart Disease: Prospective Findings From the Heart and Soul Study
Key Result
Depressive symptoms predicted higher subsequent levels of IL-6 and hsCRP in patients with coronary heart disease, but this association was eliminated (p=0.11) after adjusting for health behaviors such as physical inactivity, smoking, and body mass index.
Study Design
Type
Cohort (n=667)
Blinding
Single-blind
Structured PICO
Do depressive symptoms predict subsequent inflammation in outpatients with established coronary heart disease?
P
Population
667 older adults (mean age 66, 17.7% female) with stable coronary heart disease were followed for 5 years to evaluate the prospective association between depressive symptoms and inflammatory biomarkers.
E
Exposure
Presence of depressive symptoms (score of 10 or higher on the 9-item Patient Health Questionnaire) at one or more annual interviews over 5 years
C
Comparator
No significant depressive symptoms (score below 10 on the Patient Health Questionnaire at all interviews)
O
Outcome
Levels of three inflammatory biomarkers: fibrinogen, interleukin-6 (IL-6), and high-sensitivity C-reactive protein (hsCRP) at 5-year follow-upsurrogate
Depressive symptoms predict higher subsequent inflammation in patients with coronary heart disease, but this association appears to be mediated by poor health behaviors such as physical inactivity, smoking, and higher BMI.
Main Result
Effect estimate: F=1.74
p-value: p=0.11
Limitations
- Focused on outpatients with stable coronary heart disease, so results may not apply to healthy participants or acute coronary syndromes
- Study group mostly consisted of older men, limiting generalizability to women or younger men
- 20% of surviving participants did not complete the 5-year follow-up examination, and these dropouts were younger and had worse depression scores
Abstract
OBJECTIVE: Depression has been associated with inflammation in patients with coronary heart disease. However, it is uncertain whether depressive symptoms lead to inflammation or vice versa. METHOD: The authors evaluated 667 outpatients with established coronary heart disease from the Heart and Soul Study. Depressive symptoms were assessed annually with the 9-item Patient Health Questionnaire. Participants were categorized as having no significant depressive symptoms (score below 10 at all interviews), depressive symptoms (score of 10 or higher) at one interview, or depressive symptoms at two or more interviews. At baseline and 5-year follow-up, fasting blood samples were collected to measure three inflammatory biomarkers: fibrinogen, interleukin-6 (IL-6), and high-sensitivity C-reactive protein (hsCRP). RESULTS: Of the 667 participants, 443 had no depressive symptoms, 86 had depressive symptoms at one assessment, and 138 had depressive symptoms at two or more annual assessments. Across the three groups, greater depressive symptoms were associated with higher subsequent log-transformed levels of IL-6 and hsCRP, and the association with higher fibrinogen levels approached significance. Baseline inflammation did not predict subsequent depressive symptoms. The association of depressive symptoms with subsequent inflammation levels was eliminated after adjustment for health behaviors associated with depression-physical inactivity, smoking, and higher body mass index. CONCLUSIONS: Depressive symptoms predicted higher IL-6 and hsCRP levels among outpatients with coronary heart disease, but higher inflammation levels did not predict subsequent depressive symptoms. The association between depressive symptoms and inflammation was no longer significant after adjustment for health behaviors, which suggests these behaviors may mediate depressive effects.