Translation and validation of the 15-item Myasthenia Gravis Quality of life scale in Dutch

Validation of Spanish version of 15-item myasthenia gravis quality-of-life questionnaire

OBJECTIVES

The aim of this study was to achieve the translation and cross-cultural adaptation of the MG-QOL15R questionnaire into Spanish and the analysis of its psychometric properties.

MATERIALS AND METHODS

We recruited patients with MG, ≥18 years old, whose mother tongue was Spanish. After the translation and cross-cultural adaptation of the MG-QOL15-R, the following tests were performed: internal consistency using the Cronbach-α coefficient and corrected item-total correlations; reproducibility with a test-retest analysis using intraclass correlation coefficients; and concurrent validity using Spearman's correlation coefficient of the Spanish language MG-QOL15R-S, Myasthenia Gravis Activity of Daily Living (MG-ADL) and Quantitative Myasthenia Gravis (QMG) scores. As an approximation to construct validity, the nonparametric Mann-Whitney U test was performed between MG-QOL15R-S scores according to the Myasthenia Gravis Foundation of America classification.

RESULTS

A total of 83 MG patients were enrolled, mean age 48.19 ± 17.25 years; 58 (69.9%) were women. The mean MG-QOL15R-S score was 11.3 ± 7.1. Cronbach-α coefficient was 0.92. Item-total correlation ranged between 0.43 and 0.75. Intraclass correlation coefficient was 0.80. The Spearman correlation coefficient was 0.637 (p-value < .001) for MG-ADL and 0.487 (p-value < .001) for QMG. Mann-Whitney U tests of the mean MG-QOL15R-S scores were significantly different according to the clinical severity (p-value < .001).

CONCLUSIONS

The Spanish version of the MG-QOL15R is a valid and reliable instrument and potentially useful for measuring health-related quality of life in Spanish-speaking MG patients.

Prevalence and associated factors of fatigue in autoimmune myasthenia gravis

Fatigue is usually defined as a subjective perception of lacking energy, mentally or physically, with a difficulty sustaining voluntary activities. It is a common symptom of many diseases and most likely has a multifactorial cause. In myasthenia gravis (MG), fatigue has a high prevalence and is correlated with female sex and disease severity. However, no large scale studies have been performed. Therefore, we aimed to evaluate fatigue in the Dutch participants (n = 420) of the Dutch-Belgian Myasthenia Patient Registry using an online survey. Additional information was obtained on mood, sleep, coping, quality of life, disease severity, physical activities and medication. Severe fatigue was present in 62% with a mean score of 37.1 ± 13.2 points. Fatigue severity and prevalence increased significantly with disease severity. A positive correlation was found for female gender, BMI, disease severity and depressive symptoms. A negative correlation was found for strenuous physical activities and older age. The strong association with disease severity suggests that fatigue should be recognized as an element of the symptomatology of MG. The observed association between strenuous activity and fatigue and differences in coping style between fatigued and non-fatigued patients warrant future clinical trials on exercise and cognitive behavioral therapy.

Translation, cross-cultural adaptation, and validation of the chinese version of the 15-item myasthenia gravis quality of life questionnaire

INTRODUCTION

We sought to translate, cross-culturally adapt, and evaluate the internal consistency and validity of the Chinese version of the 15-Item Myasthenia Gravis Quality of Life (MG-QOL15).

METHODS

Translation and cross-cultural adaptation of the MG-QOL15 were performed. We used Cronbach's α to test internal consistency, one-way analysis of variance to test construct validity, and Pearson or Spearman correlations to test discriminant and concurrent validity.

RESULTS

We enrolled 168 outpatients. Internal consistency was excellent (Cronbach's α = 0.928). The MG-QOL15 discriminated MG severity as stratified by the MG Composite (MGC; P < 0.001) and Osserman class (P = 0.01). Concurrent validity was low to moderate with the subscales of the 36-item Short Form (-0.31 to ∼-0.59), MGC (r = 0.46), and Myasthenia Gravis Activities of Daily Living profile (r = 0.54).

DISCUSSION

The Chinese MG-QOL15 showed comparable construct, discriminant and concurrent validity, and internal consistency with to the original version. Muscle Nerve 59:95-99, 2019.