Shortening the Haemophilia Activities List (HAL) from 42 items to 18 items.

Introduction: The Haemophilia Activities List (HAL) was developed to measure activities and participation in persons with haemophilia (PWH). Shortening the questionnaire may facilitate use of the HAL.

Aim: The aim of this study was to determine which items of the HAL are redundant, to construct a shorter version of the HAL, and to determine the construct validity of the HAL .

Methods: A secondary analysis was performed on pooled data of two published studies using the HAL (seven domains, 42 items, optimum score: 100) in adults with haemophilia A/B. Data were divided into a derivation (62%) and a validation set (38%). Redundant items were identified by evaluation of: floor and ceiling effects, proportions of missing and 'not applicable' responses, inter-item correlations, component loadings in an exploratory factor analysis, internal consistency, and item-total correlations. Correlations with the SF-36 and EQ-5D-5L were used to determine construct validity of the HAL .

Results: Data on 680 PWH were evaluated. In the derivation dataset (n = 420), median age was 30 years (range 18-80), 43% had severe haemophilia and 61% received prophylaxis. Median (IQR) HAL sum score was 65.0 (55.7-88.8). The stepwise procedure resulted in a HAL of 18 items with a median sum score of 63.3 (54.4-86.7). Construct validity was similar for the HAL and HAL in the validation dataset (n = 260).

Conclusion: This clinimetric study resulted in a >50% shortening of the HAL. The 18-item HAL reduces patient burden and is expected to capture the information on activities and participation. The HAL needs further validation.