Validating English- and Spanish-language patient-reported outcome measures in underserved patients with rheumatic disease

Rheumatic diseases are among the most common and debilitating health problems in the United States. These diseases are chronic, can result in severe decrements of physical and psychosocial functioning and affect patients' overall quality of life. A consensus regarding the best patient outcomes to be measured in randomized, controlled trials and prospective natural history studies is essential to provide best estimates of efficacy and safety of interventions across diverse patient populations.

Face-to-face English- and Spanish-language cognitive interviews were conducted among urban Hispanic and African American patients with rheumatic disease to develop a questionnaire booklet. Six measures validating patient-reported outcomes were included: the Arthritis Self-Efficacy Scale, the Stanford Health Assessment Questionnaire Disability Index, the Wong-Baker Faces Pain Scale, the Short Acculturation Scale, the Center for Epidemiologic Studies Depression Scale and the Inventory of Complementary and Alternative Medicine Practices. A sample of patients (n = 15) attending the National Institute of Arthritis and Musculoskeletal and Skin Diseases Community Health Center participated in the initial interviews. Revised measures were further tested for reliability in a separate sample of patients (n = 109) upon enrollment at the health center.

Cognitive interviews provided feedback for questionnaire modifications and methods to enhance content validity and data quality, including discarding redundant questions, providing visual aids and concrete examples when appropriate and increasing the use of racially and ethnically concordant interviewers. The cognitive interviews further elucidated that some contextual assumptions and language usage in the original questionnaires may not have taken each respondent's environmental and sociocultural context into consideration. Internal reliability for previously tested measures remained high (Cronbach's α = 0.87-0.94).

Cognitive interviewing techniques are useful in a diverse sample of racial and ethnic minority patients with rheumatic disease as a method to assess the content validity of the specific outcome measures selected. The data collection approaches and methods described here ultimately enhance data quality. Vigilance is required in the selection of outcome measures in studies or in practice, particularly with each new language translation and/or culturally unique or diverse sample.