Estimating the minimal important change of WHODAS 2.0 in individuals with chronic stroke: a methodological comparison.

Abstract

Introduction: Assessing the state of functioning and disability post-stroke is essential for managing treatment and allocating appropriate resources.

Purpose: To explore the minimal important change (MIC) of the World Health Disability Assessment Schedule 2.0 (WHODAS 2.0) in individuals with chronic stroke using different statistical approaches.

Methods: WHODAS 2.0 was administered at baseline and after six months. MIC was estimated through distribution-based methods, anchor-based approaches, and ROC curve analysis using the Youden's index. A logistic regression model was also applied to estimate a predictive MIC (MIC_pred). Positive and negative predictive values (PPV and NPV) were estimated for three MIC thresholds.

Results: Fifty participants with chronic stroke were included (48% male; mean age approximately 60 years). Most (78%) had mild disability, and 80% showed functional improvement after six months. MIC estimates varied: 1.6 points (standard error of measurement), 5.28 points (0.33 × SD), and 8 points (0.5 × SD). ROC analysis yielded an AUC of 0.67, Youden's index of 0.35, sensitivity of 75%, specificity of 60%, and MIC ≤ 1.89 points. MIC_pred was 10.3 points (Nagelkerke R² = 0.078). The threshold of 5.28 points showed the best PPV (90.67%) and modest NPV (26.32%).

Conclusion: MIC values for WHODAS 2.0 in chronic stroke differ by method. The 5.28-point threshold offered the most balanced predictive value but should be interpreted cautiously. The findings support using multiple methods and emphasize the need for patient-centered assessment and methodological consistency in MIC determination.