Observational study of patient characteristics associated with a timely diagnosis of dementia and mild cognitive impairment without dementia.

Background: Timely diagnosis of cognitive impairment is a key goal of the National Plan to Address Alzheimer's Disease, but studies of factors associated with a timely diagnosis are limited.

Objective: To identify patient characteristics associated with a timely diagnosis of dementia and mild cognitive impairment (MCI).

Design: Retrospective observational study using survey data from the Health and Retirement Study (HRS) from 1995-2016 (interview waves 3-13).

Participants: 4,760 respondents with incident dementia and 1,864 with incident MCI identified using longitudinal measures of cognitive functioning.

Main Measures: Timely or delayed diagnosis based on the timing of a self or proxy report of a healthcare provider diagnosis in relation to respondents first dementia or MCI-qualifying cognitive score, sociodemographic characteristics, health status, health care utilization, insurance provider, and year of first qualifying score.

Key Results: Only 26.0% of the 4,760 respondents with incident dementia and 11.4% of the 1,864 respondents with incident MCI received a timely diagnosis. Non-Hispanic Black respondents and respondents with less than a college degree were significantly less likely to receive a timely diagnosis of either dementia or MCI than Non-Hispanic White respondents (dementia odds ratio (OR): 0.61, 95% CI: 0.50, 0.75; MCI OR: 0.40, 95% CI: 0.23, 0.70) and those with a college degree (dementia OR for less than high school degree: 0.30, 95% CI: 0.23, 0.38; MCI OR: 0.36, 95% CI: 0.22, 0.60). Respondents that lived alone were also less likely to receive a timely diagnosis of dementia (OR: 0.69, 95% CI: 0.59, 0.81), though not MCI. Timely diagnosis of both conditions increased over time.

Conclusions: Targeting resources for timely diagnosis of cognitive impairment to individuals from racial and ethnic minorities, lower educational attainment, and living alone may improve detection and reduce disparities around timely diagnosis of dementia and MCI.