The Synergistic Effect of Functional Status and Comorbidity Burden on Mortality: A 16-Year Survival Analysis

ObjectivesThe relationship between disability and comorbidity on mortality is widely perceived as additive in clinical models of frailty.DesignNational data were retrospectively extracted from medical records of community hospital.Data SourcesThere were of 12,804 acutely-disabled patients admitted for inpatient rehabilitation in Singapore rehabilitation community hospitals from 1996 through 2005 were followed up for death till 31 December 2011.Outcome MeasureCox proportional-hazards regression to assess the interaction of comorbidity and disability at discharge on all-cause mortality.ResultsDuring a median follow-up of 10.9 years, there were 8,565 deaths (66.9%). The mean age was 73.0 (standard deviation: 11.5) years. Independent risk factors of mortality were higher comorbidity (pConclusionsPatients with greater comorbidity and disability at discharge, discharge to nursing home or re-admission into acute care, lower socioeconomic status and being widowed had higher mortality risk. Our results identified predictive variables of mortality that map well onto the frailty cascade model. Increasing comorbidity and disability interacted synergistically to increase mortality risk.