EP2.4 Defining Thresholds and correlations for achieving MCID and PASS using iHOT12 in patients undergoing PAO for dysplasia

Abstract

Minimally Clinical Important Difference (MCID) and Patient Acceptable Symptom State (PASS) are thresholds driven from PROMS to reflect clinical effectiveness. Several methods have been described to calculate the thresholds including anchor and distribution-based methods. The heterogenicity in threshold has been highlighted in previous publications. We aim to explore 2 methods for MCID determination and 2 methods for PASS determination using the same dataset and determine % of patients achieving clinical effectiveness using different methods. Methods: 593 PAOs between 1/2013 and 7/2023 were extracted from the local Hip Preservation Registry. Patients with available PROMS 2years were included. PAOs for retroversion, residual Perthes and those combined with FO were excluded. MCID was calculated using the distribution method 0.5SD of baseline score and using 0.5 SD of mean. PASS was calculated using an anchor method, threshold determined ROC analysis performed against 2-year postoperative iHot12 and by picking value that maximizes Youden Index. A Logistic Regression analysis was performed to determine if any of the independent variables correlated with achieving MCID and PASS. Results: Using 0.5SD of baseline score the MCID threshold for iHOt12 was 8.6 with 86.3 % of patients achieving it. Using 0.5SD of change in mean the MCID was 13.5 with 77.6% of patients achieving it. The overall satisfaction was 82%. The PASS at 2 years using Youden Index method was 44 with 75.3% of patients achieving it, while using ROC analysis the threshold was 57 with 68.2% of patients achieving it. a Higher preop iHOT 12 was associated with not achieving MCID and PASS (p<0.05). Preop acetabular version was negatively correlated with achieving MCID. Conclusion: The heterogenicity in methods determining clinical effectiveness yields different thresholds. The two values for MCID for iHot 12 have been consistently replicated in the available evidence. The negative correlation with preop iHOT12 reaffirms the importance of patient selection.