Interactions between pro-inflammatory cytokines and statins on depression in patients with acute coronary syndrome

Pro-inflammatory cytokines are associated with the development of depression and statins exert anti-inflammatory and antidepressant effects. The present study aimed to investigate associations between interleukin (IL)-6 and IL-18 and depression in patients with acute coronary syndrome (ACS) and potential interactions between statin use and pro-inflammatory cytokines on depression in this population.

We used pooled datasets from 1-year follow-up data from a 24-week randomized double-blind placebo-controlled trial (RCT) of escitalopram for treatment of depressive disorder and data from a naturalistic, prospective, observational cohort study in patients with ACS. IL-6 and IL-18 levels were measured at baseline. Logistic regression models were used to investigate independent associations of IL-6/IL-18 levels with depressive disorder at baseline and at 1year. We repeated all analyses by reference to statin use to determine whether any significant association emerged.

Of the 969 participants, 378 (39.0%) had major or minor depression at baseline. Of 711 patients followed-up at 1year, 183 (25.7%) had depression. Logistic regression analysis showed that higher IL-6 and IL-18 levels at baseline were significantly associated with baseline depression after adjusting for other variables (adjusted p-values=0.005 and 0.001, respectively). IL-6 and IL-18 levels were also significantly higher in patients with depression at the 1-year follow-up after adjusting for other variables amongst those not taking statins (adjusted p-values=0.040 and 0.004, respectively); but this was not the case in patients taking statins.

Levels of pro-inflammatory cytokines appear to predict development of depression after ACS and statins attenuate the effects of cytokines on depression.