Interaction effect of the serum interleukin-6 level and anxiety on the 12-week pharmacotherapeutic responses of patients with depressive disorders

• Published in: Journal of affective disorders Vol. 308; pp. 166 - 171
• Main Authors: Choi, Wonsuk, Kang, Hee-Ju, Kim, Ju-Wan, Kim, Hee Kyung, Kang, Ho-Cheol, Lee, Ju-Yeon, Kim, Sung-Wan, Stewart, Robert, Kim, Jae-Min
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.07.2022
• Subjects: Antidepressant; Antidepressive Agents - therapeutic use; Anxiety; Anxiety - drug therapy; Depression; Depressive Disorder, Major - drug therapy; Humans; Interleukin-6; Psychiatric Status Rating Scales; Remission; Treatment Outcome; Antidepressant; Depression; Remission; Anxiety; Interleukin-6
• ISSN: 0165-0327; 1573-2517
• DOI: 10.1016/j.jad.2022.04.048

Despite the pathogenic role played by interleukin-6 (IL-6) signaling in depression, the association between baseline peripheral IL-6 signaling and the antidepressant treatment responses noted in clinical studies remains controversial. We investigated the effects of the baseline serum IL-6 (sIL-6) level and anxiety symptoms on the 12-week remission rate of depressed outpatients who received stepwise antidepressant treatments. At baseline, sIL-6 levels were measured, and anxiety symptoms were evaluated using the Hospital Anxiety Depression Scale-Anxiety subscale (HADS-A), in 1094 patients. All received stepwise antidepressant treatment. Subsequently, 12-week remission, defined as a Hamilton Depression Rating Scale (HAMD) score ≤ 7, was assessed. The individual and interaction effects of the sIL-6 level (as a binary [low vs. high, based on the median value of 1.65 pg/mL] or continuous variable) and the HADS-A score (as a binary [<12 vs. ≥12] or continuous variable) on the 12-week remission rate were analyzed using logistic regression models after adjusting for relevant covariates. Patients with both low sIL-6 levels (<1.65 pg/mL) and HADS-A scores <12 had the highest 12-week remission rate; a significant interaction effect was also apparent. This effect was significant even when the data were analyzed as continuous variables. Our study suggests that the sIL-6 level can serve as a biomarker predicting the outcome of antidepressant treatment according to the severity of anxiety symptoms. •Interaction effect of the sIL-6 level and anxiety symptoms on the 12-week remission rate of depressed patients.•Low sIL-6 level and mild anxiety were associated with the highest remission rate and showed significant interaction effect.•A combination of a low sIL-6 level and mild anxiety symptoms predicts better outcomes of antidepressant treatment.