Objectives: To examine the relationship between nursing home placement (NHP) and measures of change in other well-established clinical disease assessments in a longitudinal study of patients with probable AD.
Background: NHP is a common, major milestone in the natural history of AD. NHP is a readily identified event that can be accurately dated. NHP can be used in survival analyses, which are an efficient means of determining efficacy in clinical trials. NHP usually occurs in the setting of severe AD, but in cross-sectional studies, the strength of the association with disease severity has been controversial.
Design/methods: We used data from 341 AD patients who were enrolled in a recently published clinical trial of selegiline and tocopherol. At entry, all were rated as Clinical Dementia Rating (CDR) stage 2, were community-dwelling, and had an identified caregiver. Patients were followed at 3-month intervals for 2 years. We examined the relationship between four measures of dementia severity and a measure of behavioral dysfunction and NHP. The measures included changes in CDR status, changes in activities of daily living performance, changes from baseline to last measurement in dependence level, changes from baseline to last measurement on the Blessed Dementia Rating Scale (BDRS) score, and changes from baseline to last measurement on the total score and subscales of the Behavior Rating Scale for Dementia (BRSD). Statistical models were used to assess the strength of the associations.
Results: At the end of the 2-year period, 33% of patients had been institutionalized. The NHP patients did not differ at baseline from the not-NHP patients in gender, age, caregiver status, duration of illness, CDR sum of boxes, BDRS, or dependence level. The NHP patients had a lower baseline Mini-Mental State Examination score and a slightly worse BRSD total score. Patients reaching CDR3 were eight times more likely to be institutionalized than those who remained at CDR2. The change scores on all four dementia severity measures were strongly associated with NHP; the change score on the BRSD and its subscales were not. On the other hand, adverse events that included a behavioral disturbance, especially agitation, were associated with NHP.
Conclusion: These data show that NHP closely reflects dementia progression in the context of a clinical trial. Coupled with the high face validity of NHP as a milestone of severe dementia, NHP is a valid primary outcome measure for AD clinical trials.