Validity and reliability of Turkish version of quality-of-life
questionnaire in adult patients with common variable immune deficiency
Abstract
Background and Aims Common variable immunodeficiency (CVID) can affect
quality of life (QoL) which can be better assessed with validated
scales. Our goal was to validate the Turkish version of the Italian
CVID-QoL questionnaire. Methods International recommendations for
cultural adaptation and translation process of original scale was
followed. CVID patients completed Turkish CVID-QoL questionnaire between
October 2019 and January 2020. The Short Form Health Survey (SF-36) was
used as a comparative questionnaire. Reliability, reproducibility,
factor analysis, content validity, convergent validity and discriminant
validity were analysed. Results 50 CVID patients were included in the
study. 64 % of patients (n=32), the mean age of the patients was 36.68
± 13.2 years, the median duration of disease was 52.5 months. The
instrument had good internal consistency in 50 patients [Cronbach’s
alpha: 0.92, emotional functioning (EF): 0.91, relational functioning
(RF): 0.77]. It also revealed high reproducibility in 26 patients QoL
global, intraclass correlation coefficient (ICC)= 0.80 (95 % CI 0.56 -
0.91); EF, ICC = 0.78 (95 % CI 0.51- 0.90); RF, ICC = 0.82 (95 % CI
0.59-0.92); Gastrointestinal and skin symptoms (GSS), ICC = 0.89 (95 %
CI 0.76-0.95); (p <0.001, p <0.001, p
<0.001, p <0.001). QoL global, EF and RF scores
showed good convergent validity with similar subscales of SF-36. The
number of infections within last 3 months had a significant impact on
QoL global, EF and RF (p=0.038, p=0.045, p=0.028). Conclusions The
Turkish version of CVID QoL scale has appropriate validity and
reliability among Turkish patients with CVID.