Comparison of Scores Derived from the Box Score-11 Scale and the Pain Attribute of the Health Utilities Index-3

Background: Pain is widespread, but has not yet been the focus of measurement in terms of patient preferences. This type of measure is needed for pharmacoeconomic analyses of pain medications. Objective: Our objective was to compare scores from the Box Score (BS)-11 scale and the pain attribute of the Health Utilities Index (HUI)-3. Methods: English- and/or French-speaking adult patients (aged ≥18 years) were recruited from pain clinics in four Canadian metropolitan areas (Toronto, Ottawa, Edmonton, Vancouver). Those providing informed consent completed both pain scales, assessing their average pain level over the previous 4 weeks. Kendall’s Tau-b was calculated between score sets. Answers provided by patients were then used to determine the proportions of each of the BS- 11 scores that mapped onto each of the five HUI-3 pain scores. Results: Six of the 516 completed questionnaires had missing information, leaving 510 for analysis. The average age of patients was 49.5 ± 11.9 years; 70% were female. Tau-b was reasonably large and statistically significant between the scales (τ=0.685; p>0.001). No patients had zero scores on BS-11, and two patients scored 1, yielding inconclusive results for that score. Eight of the remaining nine BS-11 scores mapped ≥60% onto HUI-3 pain scores. BS-11 scores 2 and 10 had the best mapping (88% and 94%, respectively). Conclusions: BS-11 scores can be mapped onto the pain attribute of the HUI-3 with a high degree of correlation. Copyright Adis Data Information BV 2011