Responsiveness of the Japanese Osteoporosis Quality of Life questionnaire in women with postmenopausal osteoporosis

Background: The Japanese Osteoporosis Quality of Life (JOQOL) questionnaire measures quality of life in Japanese patients with osteoporosis. However, several important aspects of the psychometric properties of individual domains, including responsiveness, have not been addressed to enable valid clinical application. This analysis examined the internal and external responsiveness of the JOQOL questionnaire. Methods: This was a post hoc analysis of a 24-week prospective postmarketing study of raloxifene (60 mg/day) administered to postmenopausal Japanese women with osteoporosis (JapicCTI-070465). Internal responsiveness was assessed using Standardized Response Mean (SRM) statistics and changes in JOQOL domain scores. Patients were also stratified into those who did or did not achieve a minimal clinically important change (MCIC) in pain, assessed by a visual analogue scale for pain (VAS pain): comparisons were made between treated patients who achieved VAS pain reduction ≥ 20 mm versus VAS pain reduction < 20 mm. External responsiveness was assessed using Pearson's correlation coefficient (r) for changes in JOQOL domain scores with Short Form-8 Health Survey and European Quality of Life Instrument scores. Results: Of 506 patients analyzed, 421 had a baseline value for VAS pain; of these, 152 patients (36.1%) had a MCIC, whereas 264 patients (62.7%) did not. The JOQOL domains pain, overall health, and falls/psychological factors had small to moderate SRM values (0.3-0.5) in all patients, but consistently showed significantly larger changes in patients whose pain score changes exceeded the MCIC. Together, these findings suggest some degree of internal responsiveness for these domains. However, activities of daily living domain had a SRM value as low as 0.2, and recreation/social activities and posture/physique domains had SRM values close to 0. Moderate correlation (defined as r ≥ 0.4 to < 0.6) was noted between the domains pain, activities of daily living, and overall health and some Short Form-8 Health Survey subscales and the European Quality of Life total score, suggesting external responsiveness of these domains. Conclusions: The inconsistent responsiveness among individual JOQOL domains in treated patients suggests the need for improving several JOQOL domains, especially the activities of daily living, recreation/social activities and posture/physique domains, before application to clinical research.