Risk factors for nursing home placement in a population-based dementia cohort

OBJECTIVE: To examine risk factors for nursing home placement in a population-based dementia cohort. METHODS: The Mayo Clinic Medical Records linkage system was used to identify all patients with onset of dementia between 1980 and 1984. The patient group included 314 cases who met DSM-III-R criteria for dementia, including 220 cases who were community dwelling at onset. All dementia patients were followed until death. A control group included 323 patients who did not, at any point, meet DSM-III-R criterion for dementia. The groups were initially matched on age, gender, and year of initial registration. Demographic, medical, social, and functional predictors were examined as static and time-dependent risk factors for nursing home placement in the initial community-dwelling subgroups, using stepwise Cox regression modeling. RESULTS: Of the 314 dementia patients, 282 took residence in licensed skilled nursing homes for at least 6 weeks, suggestive of custodial care, at some point during the course of their illness. In the control group, 162 of the 323 people required nursing home placement. Within controls, the predictor variables of time to nursing home placement included initial age, being divorced, living in a townhome, apartment or assisted living apartment, change in Charlson comorbidity score, and change in amount of daily assistance required. Within the dementia sample, seven predictors were eventually determined to be associated with time to nursing home placement. These included total number of years of education, age at onset of dementia, being single, living in a retirement or supervised apartment at onset, change in Charlson comorbidity score, and a change in the amount of daily assistance required. CONCLUSIONS: Cumulative incidence of placement was 90% in the dementia cohort and 50% in the controls. Certain variables seem to impact time to nursing home placement in all older persons, whether they have dementia or not. Among these are age, living in assisted living settings, increasing comorbidity scores, and increasing need for functional assistance. Certain additional factors may have a specific impact in dementia. Among these is education, which seems to provide a protective effect. These predictors may be important covariates in clinical dementia studies that include time to nursing home placement as an outcome variable.