Literacy-Fair Measurement of Health-Related Quality of Life Will Facilitate Comparative Effectiveness Research in Spanish-Speaking Cancer Outpatients

Abstract

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. To compare HRQL responses across literacy levels in Spanish-speaking patients with cancer using a multimedia touch screen program. A total of 414 adult patients with cancer (213 with low literacy and 201 with high literacy). 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. 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. 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.