Lewy body dementia (LBD) is the second most common degenerative dementia in people over 65 (1,2). LBD is underdiagnosed, with only one third of patients correctly diagnosed in daily clinical practice (3); data on the distribution of the disease are scarce. Our study was designed to measure the incidence, prevalence and clinical characteristics of LBD in south-eastern Spain. Healthcare system in Spain is free and universal.

Prospective epidemiological study of LBD in San Vicente del Raspeig between October 18, 2021, and October 17, 2022. The total population aged 60 or over based on the 2019 census was 11445 inhabitants (5227 males, 6218 females). Diagnosis of LBD was based on 2017 McKeith criteria. Only “probable” cases were registered for greater diagnostic certainty. Incidence was studied for the one-year period. Collected data included gender, age, cardinal symptoms for LBD, abnormal biomarkers, neuropsychiatric symptoms, medical treatment, years from diagnosis and GDS score (Reisberg) in the last visit. Protocol was approved by the ethical committee.

Global prevalence was 0.67% among the population over 60. Annual incidence was 3.2/1000 person-year.

Mean age of prevalent cases was 78 years (SD 7.5). 68.8% were studied with at least one biomarker (mainly 123I-ioflupane and less frequent polysomnography or MIBG gammagraphy); most suffered 2 or 3 core symptoms (79.2%) (in descending order: parkinsonism, visual hallucinations, rapid eye movement sleep behavior disorder and fluctuations). Two out of five prevalent cases were in an early phase of the disease: 22.1% in mild cognitive impairment (MCI) and 16.9 % in mild dementia. Mean me of disease was 1.9 years (SD 2.2). Other neuropsychiatric symptoms appeared in up to 74% of patients (apathy 18,2%, anxiety 19,5%, depression 23,4%, minor hallucinations 22%, delusions 17%, auditory and tactile hallucinations 1,2%).

Prevalence is in line with previous reports. Higher incidence than previously reported may be due to high attention on MCI-LBD and our expertise as a referral Memory Unit. We found a wide dominance of aged women and high prevalence of neuropsychiatric symptoms.