523. Estimating clinically important differences in the adult attention deficit hyperactivity disorder self-report scale
Abstract
Abstract Background The adult attention deficit hyperactivity disorder (ADHD) self-report scale (ASRS), as one of the widely used patient-reported outcome measures (PROMs), played an important role in evaluating ADHD symptom severity and treatment-related changes in clinical trials of adults with ADHD, while the clinically important differences (CIDs) remain poorly defined. Aims & Objectives In this study, we aim to review the updated applications of the CID for ASRS in randomized controlled trials (RCTs) and to establish the CID for ASRS in adults diagnosed with ADHD. Method Firstly, we conducted a cross-sectional literature search to survey the status of RCTs for adult ADHD interventions to assess the inclusion and appropriate interpretation of CID values. Then, we conducted a secondary analysis of the RCT involving 56 adults with ADHD who received either active or sham transcranial alternating current stimulation (tACS) from our team. The PROM was the ASRS total score. An anchor-based approach using the Clinical Global Impression-Improvement (CGI-I) was applied. General linear mixed-effects modeling estimated mean differences across patient-defined improvement levels and were used to identify different categoric CID thresholds. Results None of 11 studies reported CID with ASRS as PROM on adults with ADHD. The finding from mixed-effects model suggested that a reduction of approximately 13.4-points in ASRS total score represents a clinically meaningful improvement (CID within-group), and 19.5-points as much improvement, and referred to a change rate of ASRS total score from baseline to end of treatment of 29.2% for improvement and 42.6% for much improvement. Also, a difference of 5.7-point in ASRS total score represents a minimal clinically meaningful difference (CID between-group), and 12.3-point as moderate meaningful difference between two groups. Discussion & Conclusions This study provides adults ADHD specific CID estimates that offers practical benchmarks for interpreting treatment response and power calculations, and represents evidence-based endpoint for future clinical trials in adults ADHD.