Using patient-reported outcome measures to identify mobility limitation in incurable cancer

Objectives To i) examine the relationship between a single-item and multi-component patient-reported outcome measure (PROM) for mobility; ii) identify mobility profiles (PROM-defined patterns of mobility difficulty)using these measures; and iii) 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 tumours, Eastern Cooperative Oncology Group (ECOG) 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 Measure(s) Mobility was assessed using the Integrated Palliative Care Outcome Scale (IPOS) mobility item and the World Health Organisation 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 (FACT-G). 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 FACT-G 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.