Comorbidity of Dementia: A Cross-Sectional Study of PUMCH Dementia Cohort

Background: Comorbidities reduce quality of life for people with dementia and caregivers. Some comorbidities share a genetic basis with dementia. Objective: The objective of this study is to assess comorbidity in patients with different dementia subtypes in order to better understand the pathogenesis of dementias. Methods: A total of 298 patients with dementia were included. We collected some common comorbidities. We analyzed the differences in comorbidities among patients with dementia according to clinical diagnosis, age of onset (early-onset: <  65 and late-onset: ≥65 years old) and apolipoprotein (APOE) genotypes by using the univariate and multivariate approaches. Results: Among 298 participants, there were 183 Alzheimer’s disease (AD), 40 vascular dementia (VaD), 37 frontotemporal dementia (FTLD), 20 Lewy body dementia (LBD), and 18 other types of dementia. Based on age of onset, 156 cases had early-onset dementia and 142 cases had late-onset dementia. The most common comorbidities observed in all dementia patients were hyperlipidemia (68.1%), hypertension (39.9%), insomnia (21.1%), diabetes mellitus (19.5%), and hearing impairment (18.1%). The prevalence of hypertension and cerebrovascular disease was found to be higher in patients with VaD compared to those with AD (p = 0.002, p <  0.001, respectively) and FTLD (p = 0.028, p = 0.004, respectively). Additionally, patients with late-onset dementia had a higher burden of comorbidities compared to those with early-onset dementia. It was observed that APOE ɛ4/ɛ4 carriers were less likely to have insomnia (p = 0.031). Conclusions: Comorbidities are prevalent in patients with dementia, with hyperlipidemia, hypertension, insomnia, diabetes, and hearing impairment being the most commonly observed. Comorbidity differences existed among different dementia subtypes.