# Disease burden in Serbian patients with facioscapulohumeral muscular dystrophy

## TL;DR

This study adapts and validates a disease-specific health index for Serbian patients with facioscapulohumeral muscular dystrophy to better assess their disease burden.

## Contribution

The study validates the Serbian version of the FSHD-HI as a reliable and valid tool for measuring disease burden in FSHD patients.

## Key findings

- The Serbian version of FSHD-HI (FSHD-HI-RS) demonstrated excellent internal consistency and test-retest reliability.
- FSHD-HI scores correlated strongly with disease duration, muscle strength, and clinical evaluation measures.
- The FSHD-HI-RS effectively captures disease-specific features not fully addressed by generic quality of life questionnaires.

## Abstract

This study aimed to adapt the Facioscapulohumeral Muscular Dystrophy - Health Index (FSHD-HI) for Serbian patients with facioscapulohumeral muscular dystrophy (FSHD) in order to measure their disease burden.

Forty-one patients with genetically confirmed FSHD1 were included in the study. Validation involved reliability analysis (internal consistency), content validity, construct validity, and criterion validity analyses. The Comprehensive Clinical Evaluation Form (CCEF) was employed to capture various FSHD phenotypes. All patients completed the Serbian version of the Short Form Health Survey (SF-36) questionnaire, serving as a generic measure of the health-related quality of life (QoL).

All patients found Serbian version of FSHD-HI (FSHD-HI-RS) understandable and that the language was appropriate and simple. The internal consistency of FSHD-HI-RS was excellent for the whole questionnaire (Cronbach’s alpha >0.90). Test–retest reliability met the required level (intraclass correlation coefficient 0.91). FSHD-HI scores showed significant correlations with disease duration (rho = 0.564, p < 0.01), muscle strength measured with Medical Research Council (MRC) sum score (rho = −0.708, p < 0.01), and CCEF (rho = +0.716, p < 0.01). FSHD-HI total score correlated significantly with the total SF-36 score (rho = −0.733, p < 0.01).

Our data demonstrate that FSHD-HI-RS is an understandable, reliable, and valid measure of the disease burden in FSHD. It is easy to administer and complete, and it can capture disease-specific features that may be omitted with generic QoL questionnaires.