Association between ambulatory status and health-related quality of life in patients with bone metastases: A prospective observational study.

BACKGROUND: Bone metastasis is a leading cause of Cancer Locomo (locomotive syndrome in cancer patients). Although impaired ambulation is clinically important in patients with bone metastases, its association with patient-reported physical and mental quality of life remains insufficiently characterized. This study examined the cross-sectional association between ambulatory status and health-related quality of life using baseline data from patients with bone metastases. METHODS: This prospective observational study included patients with bone metastases referred for orthopaedic consultation. Ambulatory status was assessed using the Functional Ambulation Categories, and health-related quality of life was assessed using the Short Form-8. Physical Component Summary (PCS) and Mental Component Summary (MCS) scores were compared between non-ambulatory and ambulatory patients. Multivariable linear regression estimated adjusted mean differences in PCS and MCS scores according to ambulatory status, adjusting for age, sex, and primary tumor category. Sensitivity analyses additionally adjusted for spinal metastasis and painful spinal metastasis. RESULTS: Of 90 registered patients, 68 with complete baseline ambulatory status and Short Form-8 data were analyzed; 12 were non-ambulatory. After adjustment, non-ambulatory status was associated with lower PCS (β = -14.95, 95% CI -19.81 to -10.10, P < 0.001) and MCS scores (β = -6.26, 95% CI -11.44 to -1.07, P = 0.019). These associations were not materially changed after additional adjustment for spinal metastasis or painful spinal metastasis. In a descriptive 3-month follow-up of six non-ambulatory patients, five regained ambulatory ability with concurrent increases in PCS and MCS scores. CONCLUSIONS: In this cross-sectional analysis of baseline data, non-ambulatory status was associated with lower physical and mental quality of life. Ambulatory status may help identify patients with lower health-related quality of life. However, reverse causation and residual confounding cannot be excluded. Further longitudinal studies are needed to clarify the temporal relationship between changes in ambulatory status and changes in quality of life.