Exploratory analyses of potential moderators of a personalized intervention to reduce preoperative anxiety: a secondary analysis of a randomized clinical trial

Abstract This exploratory secondary analysis investigated whether individual patient characteristics might moderate the effectiveness of a personalized, information-based intervention aimed at reducing preoperative anxiety. The study included 122 patients scheduled for elective surgery. Anxiety was assessed repeatedly before surgery using the Amsterdam Preoperative Anxiety and Information Scale alongside numeric rating scales, capturing surgery-related anxiety, anesthesia-related anxiety, and overall anxiety. Constrained linear mixed models were applied to evaluate potential moderating effects of sociodemographic (e.g., education), psychological (e.g., neuroticism, depression, need for information, perceived physician competence and warmth), and clinical variables (e.g., smoking status, previous surgeries, type of surgery, chronic pain, premedication). The intervention consisted of a structured conversation supplemented by optional video material. The analyses provided little evidence that intervention effects systematically differed according to the examined patient characteristics. Among the examined moderators, chronic pain yielded the strongest indication of potential effect modification with regard to anesthesia-related anxiety outcomes. However, these findings did not remain statistically significant after correction for multiple testing and should therefore be considered exploratory and hypothesis-generating. Overall, the present findings provide no confirmatory evidence that the effectiveness of the intervention differs systematically across the examined patient characteristics. Future adequately powered studies are needed to determine whether specific patient characteristics influence response to personalized preoperative anxiety interventions.