RESUMEN
BACKGROUND: Multimorbidity is highly prevalent in older adults, both those with and without cancer, and is associated with an increased risk of mortality. The aim of this study was to investigate if multimorbidity measures in geriatric rehabilitation inpatients differ in their association with mortality, dependent on a diagnosis of cancer. METHODS: REStORing health of acutely unwell adulTs (RESORT) is an ongoing longitudinal inception cohort of geriatric rehabilitation inpatients. Comorbidity was measured at admission using the Charlson Comorbidity Index (CCI), age-adjusted CCI (CCI-A), Cumulative Illness Rating Scale-Geriatrics (CIRS-G) and the CIRS-G severity index. Patients were allocated to a cancer status group (no cancer, history of cancer, or active cancer). The association of comorbidity indices with mortality was analyzed using Cox regression analyses. RESULTS: Of the 693 patients (mean age 82.2 ± 7.5 years), 523 (75.4%) had no history of cancer, 96 (13.9%) past cancer, and 74 (10.7%) active cancer. Three months post-discharge, patients with active cancer had a higher mortality risk compared to patients with no cancer (HR = 3.57, 95% CI 2.03-6.23). CCI and CCI-A scores were significantly associated with higher mortality risk in all cancer status groups. CONCLUSION: In geriatric rehabilitation patients, incremental CCI and CCI-A scores were associated with higher mortality in all three cancer status groups. However, patients with active cancer had a significantly higher 3-month mortality compared to those with no or past cancer, and this is likely determined by the advanced nature of the malignancies in this group.