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.