Serbian Validation of the Individualized Neuromuscular Quality of Life Questionnaire (INQoL) in Adults With Myotonic Dystrophy Type 1

Abstract

Background: To validate Individualized Neuromuscular Quality of Life Questionnaire (INQoL) in Serbian patients with myotonic dystrophy type 1 (DM1).

Methods: This study included 102 patients with adult onset DM1. Validation included reliability analysis (internal consistency, reproducibility), content-related validity (psychometric evaluation, construct-related validity, criterion-related validity) and concurrent validity.

Results: The internal consistency of the Serbian version of INQoL was excellent (Cronbach’s alpha 0.864-0.961). Test-retest reliability satisfied the requested level (intraclass correlation coefficient 0.713-0.979). Item internal consistency and discriminant validity were excellent. INQoL scores were significantly affected by age of patients, duration of disease and severity of muscular impairment (P less than 0.01), slightly affected by education (P less than 0.05) and not related to gender (P greater than 0.05). Correlation between INQoL scales and comparable SF-36 domains was significant (P less than 0.01) but INQoL also registered locking and body image omitted by SF-36.

Conclusion: Serbian version of INQoL is reliable and valid quality of life (QoL) measure for patients with DM1, able to capture disease specific issues usually omitted by generic questionnaires.




doi:10.4021/jnr54w