Literacy-fair measurement of health-related quality of life will facilitate comparative effectiveness research in Spanish-speaking cancer outpatients

Background: Health-related quality of life (HRQL) assessment is frequently used in comparative effectiveness research, but low-literacy patients are often excluded. Appropriately translated and user-friendly HRQL measures are essential to ensure inclusion of low-literate and non-English-speaking patients in comparative effectiveness research. Objectives: To compare HRQL responses across literacy levels in Spanish-speaking patients with cancer using a multimedia touch screen program. Subjects: A total of 414 adult patients with cancer (213 with low literacy and 201 with high literacy). Research Design: The touch screen system administered 3 questionnaires: The Functional Assessment of Cancer Therapy-General, the Short Form-36 Health Survey, and the Standard Gamble Utility Questionnaire. Measurement bias was evaluated using item response theory. Effects of literacy on HRQL were evaluated using regression models. Results: Patients rated the touch screen easy to use and commented favorably on the multimedia approach. There was statistically significant item response theory measurement bias in 6 of 10 HRQL subscales; however, only 3 showed meaningful bias. Low-literacy patients had significantly lower mean scores on 3 of 4 Functional Assessment of Cancer Therapy-General subscales, before and after adjustment for patient characteristics. Low-literacy patients also had significantly lower mean scores on 5 of 6 Short Form-36 subscales; adjustment for patient characteristics attenuated or eliminated differences. Similar proportions of low- and high-literacy patients valued their current health as equivalent to perfect health. Conclusions: This study demonstrates the feasibility of this multimedia touch screen program for low-literacy patients. The program will provide opportunities to evaluate the effectiveness of interventions in more diverse patient populations.