Using Patient-Reported Outcome Measures to Identify Mobility Limitation in Incurable Cancer.

OBJECTIVES: To (1) examine the relationship between a single-item and multicomponent patient-reported outcome measure (PROM) for mobility; (2) identify mobility profiles (PROM-defined patterns of mobility difficulty) using these measures; and (3) explore associations between demographic or clinical characteristics and mobility profiles. DESIGN: Analysis of baseline data from an ongoing multinational trial of a rehabilitation intervention for people with incurable cancer. SETTING: Oncology and palliative care outpatient services participating in an international rehabilitation trial. PARTICIPANTS: A consecutive sample of 211 adults with incurable solid tumors, Eastern Cooperative Oncology Group Performance Status 2-3, and a clinician estimated prognosis of ≥3 months. Of these, 206 had complete mobility data and formed the analytic sample. MAIN OUTCOME MEASURES: Mobility was assessed using the Integrated Palliative Care Outcome Scale (IPOS) mobility item and the World Health Organization Disability Assessment Schedule (WHODAS 2.0) mobility subdomain; higher scores reflect greater mobility limitation or difficulty. Secondary outcomes included WHODAS 2.0 self-care and participation scores and quality of life measured using the Functional Assessment of Cancer Therapy-General. RESULTS: IPOS and WHODAS 2.0 mobility scores were positively correlated (ρ=0.650; 95% CI, 0.55-0.74; P<.001). Five mobility profiles were identified (Silhouette≈0.6), each defined by a single IPOS score (0-4) and WHODAS 2.0 mean scores ranging from 8.3 (SD, 3.7) to 19.3 (SD, 3.9). These groups primarily reflected a graded spectrum of mobility difficulty rather than distinct patterns. WHODAS 2.0 self-care, participation, and Functional Assessment of Cancer Therapy-General scores did not significantly differ by mobility profile. However, younger patients and those using mobility devices were represented more in mobility profiles with greater perceived mobility difficulty. CONCLUSIONS: A single-item PROM identified broad functional limitations and may help identify mobility profiles among people with incurable cancer. These findings support the utility of the IPOS mobility item as a tool that may help clinicians screen for difficulties with mobility and determine when detailed assessment or rehabilitation input is warranted. The PROM-defined mobility profiles should be interpreted as exploratory stratification and not as independently validated clinical subtypes. Further studies should validate the mobility profiles' stability and clinical usefulness in longitudinal cohorts.