Clinical phenotypes of depressed patients with evidence of inflammation

Background
Whether depressed patients with evidence of inflammation are more appropriate candidates for immunotherapies is being tested in clinical trials. However, studies of the clinical and phenotypic profile of depressed patients with evidence of inflammation are relatively scarce.
Methods
We investigated clinical characteristics of 84 patients meeting International Classification of Diseases 10th Revision criteria for current depressive episode, grouped as those with and without evidence of inflammation.
Results
After adjusting for potential confounders, regression analyses showed that inflammation (C-reactive protein ≥ 3mg/L) was associated with higher depression severity (adjusted mean difference=8.82; 95% CI, 3.91-13.72), somatic symptoms (adjusted mean difference=3.25; 95% CI, 1.58-4.92), state anxiety (adjusted mean difference=9.25; 95% CI, 3.82-14.67), perceived stress (adjusted mean difference=4.58; 95% CI, 1.98-7.18), and fatigue (adjusted mean difference=9.71; 95% CI, 3.09-6.33), but not anhedonia. This group also had poorer quality of life (adjusted mean difference=-0.18; 95% CI, -0.32-0.05). At individual depressive symptom level, the inflammation group had increased guilty feelings (adjusted OR=7.28; 95% CI, 2.09-31.17), pessimism (adjusted OR=5.38; 95% CI, 1.53-22.73), concentration difficulties (adjusted OR=4.56; 95% CI, 1.32-19.02), and indecisiveness (adjusted OR=4.21; 95% CI, 1.15-18.54).
Conclusions
We highlight clinical features associated with inflammation-related depression. These results could aid patient selection in future clinical trials testing immunotherapies in depression. Replication of these findings in larger samples is required.