Persistence of neuropsychiatric symptoms and dementia prognostication: A comparison of three operational case definitions of mild behavioral impairment

INTRODUCTION: We compared three operational case definitions of mild behavioral impairment (MBI) in the context of MBI prevalence estimates and dementia risk modeling. METHODS: Participants were dementia‐free older adults (n = 13701) from the National Alzheimer's Coordinating Center. Operational case definitions of MBI were generated based on neuropsychiatric symptoms at one (OV), two‐consecutive (TCV), or more than two‐thirds (TTV) of dementia‐free study visits. Definitions were compared in prevalence and in Cox regressions using MBI to predict incident dementia. RESULTS: OV MBI was the most prevalent (54.4%), followed by TCV (32.3%) and TTV (26.7%) MBI. However, OV MBI had the lowest rate of incident dementia (hazard ratio [HR] = 2.54, 95% confidence interval [CI]: 2.33–2.78) and generated poorer model metrics than TCV MBI (HR = 4.06, 95% CI: 3.74–4.40) and TTV MBI (HR = 5.77, 95% CI: 5.32–6.26). DISCUSSION: Case ascertainment with longer timeframe MBI operational case definitions may more accurately define groups at risk of dementia in datasets lacking tools designed to detect MBI. HIGHLIGHTS: Mild behavioral impairment (MBI) can identify older adults at risk of dementia. Neuropsychiatric symptom (NPS) assessment tools can be proxy measures for MBI. Hazard for dementia was highest for MBI defined by NPS presence at more than two‐thirds of visits.