The study was designed to adapt the Stanford Health Assessment Questionnaire (HAQ) and the Rheumatoid Arthritis Quality of Life Questionnaire (RAQoL) for use in Denmark.
The instruments were translated into Danish and then field-tested with 10 RA patients for relevance, and face and content validity. Reliability and validity were assessed by administering the new measures and a comparator instrument (the Danish Nottingham Health Profile) to 80 RA patients on two occasions.
Patients found both measures acceptable and easy to complete. They had good test-retest reliability (>0.90) and internal consistency and were both able to discriminate between groups with different levels of functional status and self-perceived severity. When compared with the NHP sections, both measures showed expected convergence and divergence.
Given the excellent psychometric properties of the Danish versions of the RAQoL and HAQ, both are recommended for inclusion in clinical trials and studies.