A0411
Title: Evaluation of the natural history of disease by combining incident and prevalent cohorts: Application to the Nun Study
Authors: Daewoo Pak - Yonsei University (Korea, South) [presenting]
Abstract: The Nun study is a well-known longitudinal epidemiology study of ageing and dementia that recruited elderly nuns who were not yet diagnosed with dementia (i.e., incident cohort) and had dementia prior to entry (i.e., prevalent cohort). In such a natural history of disease study, multistate modelling of the combined data from both incident and prevalent cohorts is desirable to improve inference efficiency. While important, the multistate modelling approaches for the combined data have been scarcely used in practice because prevalent samples do not provide the exact date of disease onset and do not represent the target population due to left truncation. It is demonstrated how to adequately combine both incident and prevalent cohorts to examine risk factors for every possible transition in studying the natural history of dementia. A four-state nonhomogeneous Markov model is adapted to characterize all transitions between different clinical stages, including plausible reversible transitions. The estimating procedure using the combined data leads to efficiency gains for every transition compared to those from the incident cohort data only.
