Aim: We evaluated a previously reported digestive health status instrument
in community, primary care, and gastroenterology practice populations. Mult
iple types of reliability, validity and responsiveness were assessed to det
ermine the performance of the questionnaire.
Methods: Study populations included community, primary care and gastroenter
ology subjects. Psychometric analyses included internal consistency and tes
t-retest reliability, criterion and construct validity, and responsiveness,
Results: Acceptable internal consistency was seen on all scales in all thre
e populations. Test-retest reliability was excellent in a speciality popula
tion with reflux disease. Criterion validity was demonstrated by strong cor
relation of reflux scale scores and results on 24-h pH monitoring. Scale sc
ores varied predictably in those receiving gastrointestinal tract imaging a
nd according to diagnosis, indicating construct validity. The reflux scale
and pain index were sensitive to change with treatment for reflux disease.
Multi-trait scaling analyses from the community sample revealed a structure
equivalent to that reported from a primary care sample.
Conclusions: The reliability and validity of the digestive health status in
strument on multiple measures in multiple settings have been demonstrated.
The instrument was responsive to change with treatment for reflux disease.
The demonstrated robustness attests to the suitability for future studies a
nd clinical application.