[Development of disease burden score concerning bone and joint diseases: comparison between rheumatoid arthritis and osteoarthritis].

Objectives: To develop disease burden score concerning bone and joint diseases by evaluating the burdens of rheumatoid arthritis (RA) and osteoarthritis (OA) based on two quantitative measures of quality of life (QOL).

Methods: In a questionnaire, the qualified doctors of Japan Rheumatism Foundation were asked to evaluate patients' QOL, including 6 items of physical functions, 7 items of daily living activities and 3 items of social activities, for three severity levels defined by treatment status. The burdens of RA and OA were determined based on two quantitative measures of QOL, that is, 'principal component score' and '0-0.5-1 score'.

Results: In the two-way ANOVA of severity level and doctor's specialism, two quantitative measures of QOL showed significant differences by severity level, having approximately the same F-statistics each other. The burden of RA was 1.4-times (for 'principal component score') and 1.6-times (for '0-0.5-1 score') as great as that of OA. The differences in burden between RA and OA were observed especially in daily living activities and social activities.

Conclusions: Our methodology may be applicable to examining differences in burden between bone and joint diseases.