Diagnostic diversity among patients with cognitive complaints: A 3-year follow-up study in a memory clinic

To describe the distribution and estimate the mortality risks of degenerative dementias and nondegenerative conditions in a memory clinic.

We enrolled 727 consecutive patients with cognitive complaints who visited the memory clinic in Buddhist Tzu Chi General Hospital during 2013 to 2016. Three main diagnostic groups were defined: pure type dementia, in which only one type of dementia was diagnosed, such as Alzheimer disease (AD), vascular dementia (VaD), Parkinson disease with dementia (PDD), dementia with Lewy bodies (DLB), and frontotemporal dementia (FTD); mixed type dementia; and nondegenerative conditions. We described the frequency of different diagnoses and employed Cox proportional hazards regression models to examine the mortality risks for each diagnostic group after adjusting for age, sex, education, and cognitive status. All patients alive on or after September 30, 2018, were censored in the analysis.

Two-thirds of patients (n = 496, 68.2%) were diagnosed with degenerative dementias. Pure type to mixed type dementia ratio was about 2: 1. AD remained the most common pure dementia subtype, followed by VaD and PDD. Among all nondegenerative conditions, depression/anxiety and subjective cognitive decline were the most common diagnoses. During a mean follow-up of 3.4 years, 150 deaths were documented, and the mortality risk was 61 deaths/1000 person-years. Mortality risks were associated with age, sex, education, and cognitive function at diagnosis but did not differ by diagnostic group.

Clinical diagnoses for patients with cognitive complaints are diverse, and nearly one-third are of nondegenerative conditions. Baseline cognitive function is a stronger predictor for survival than clinical diagnosis.