Beyond pharmacology: The mediating role of expectations in the experience of side effects in anxious patients treated with secukinumab.

INTRODUCTION: Biologics such as the interleukin-17A inhibitor secukinumab have significantly advanced the treatment of psoriasis. However, when discussing treatments, the role of expectations in the perception of side effects is not yet entirely clear. It is known, however, that negative expectations can cause nocebo effects. We investigated whether side-effect expectations mediate the relationship between trait anxiety and the reporting of side effects during secukinumab therapy.

METHODS: This post-hoc analysis used data from a randomized controlled trial in adults with moderate-to-severe plaque psoriasis. At the start of the study, trait anxiety and expectations regarding side effects were assessed; self-reported side effects were recorded at weeks 4 and 16. The side-effect outcomes were square-root-transformed prior to analysis to address distributional skew. All mediation steps were estimated using linear regression.

RESULTS: Data from N = 104 participants were analyzed. Higher trait anxiety was associated with more self-reported side effects at week 4, but not at week 16. The association at week 4 was mediated by expectations regarding side effects assessed at baseline.

CONCLUSION: The results indicate a nocebo effect in more anxious patients in the first weeks of treatment, with anxiety linked to negative treatment expectations which in turn were associated with the experience of side effects. Over time, the level of experienced side effects decreased significantly, potentially due to positive learning experiences occurring over the course of the treatment. Our findings emphasize the significance of targeted patient-centred communication to optimize treatment adherence.