Translation and validation of the Serbian primary biliary cholangitis-40 questionnaire

Background and aims: To translate into Serbian and validate the Primary Biliary Cholangitis–40 (PBC-40) and PBC-27 questionnaires. Materials and methods: Ninety-four consecutive outpatients with the diagnosis of PBC from three departments across two tertiary care institutions in Belgrade were enrolled from February to October 2016. Standard methodology for cultural adaption of healthcare related quality of life questionnaires was used, and included: a forward translation, backward translation and a pilot test of the Serbian PBC-40 on five patients who gave suggestions and comments. For evaluation of the questionnaires, acceptance was shown by the proportion of missing items and the internal consistency was assessed using Cronbach’s α coefficient. The PBC-40 was self-administered under the supervision of an experienced hepatologist. The PBC-27 is a shorter version of the PBC-40. Results: A total of 92 (97.9%) of the patients were females. The mean age was 59.26 ± 1.05 years and the average length of disease was 60.45 ± 48.314 months. The average PBC-40 score was 85.62 ± 30.46. The total time needed to complete the questionnaire ranged from 7 to 16 minutes. The proportion of missing items was 5.45% (205/3760). Cronbach’s α for the entire scale was 0.93. Reliability for all of the domains of the PBC-40 was above 0.70, except for the domain “Symptoms” (α = 0.52). Overall reliability of the PBC-27 was α = 0.90. Domains “Dryness”, “Symptoms” and “Fatigue” demonstrated reliability below α = 0.70. Conclusions: The Serbian PBC-40 is a valid and reasonably adequate for use in Serbian PBC patients. The PBC-40 is preferred over the PBC-27.