Quality of life is associated with chronic inflammation in depression: A cross-sectional study.

Background: Inflammation may play a crucial role in the pathophysiology of depression. However, the association between chronic inflammation and health outcomes in depression remains unclear, particularly for patient-reported outcomes.

Methods: The aim of this study was to investigate the relationship between quality of life (QoL) (physical and mental health, assessed by the SF-36) and chronic inflammation assessed using C-reactive protein (CRP) in patients with current major depressive disorder.

Results: One hundred eighty-one patients with depression were enrolled in this study. After adjusting for key socio-demographic, clinical and biological confounding factors, patients with high levels of CRP (> 3.0mg/L) had worse physical health than those with normal CRP levels (OR = 0.95, 95% CI = 0.92-0.99). Significant associations were found between a higher rate of metabolic syndrome (OR = 0.10, 95% CI = 0.02-0.41) and high CRP levels.

Limitations: The cut-off point for high cardiovascular risk was used to define the two groups: normal CRP level and high CRP level. CRP was the sole marker of inflammation in this study and was collected at only one time point. The design of this study is cross-sectional and there are no conclusions about the directionality of the association between QoL and inflammation in depression. QoL was assessed only by SF-36 scores.

Conclusion: This study found an association between SF-36 physical health score and CRP in patients with depression, thereby showing the need to consider physical well-being in depression. This paves the way for interventions to act both on inflammation and QoL in patients with depression.