Risk factors of dementia in patients with cerebral vascular diseases based on Taiwan National Health Insurance data

INTRODUCTION: Vascular factors have been shown to be associated with increased risk of dementia. However, clinical trials have so far been unsuccessful, suggesting new approaches are needed. The aim of this study was to use population-based real world data to investigate risk factors and preventive factors for dementia, including the effects of traditional Chinese medicine)(TCM). METHODS: This is a retrospective cohort study using LHID2000, a dataset randomly selected from Taiwan's National Health Insurance Research Database (NHIRD). Subjects with occlusion and stenosis of precerebral and cerebral arteries, cerebral atherosclerosis without mention of cerebral infarction, and transient cerebral ischemia were included. Subjects with dementia at baseline were excluded. The primary endpoint was dementia. Data for demographic and clinical comorbid status and treatments administered at baseline in 2000 and at the end of follow-up in 2013 were included. RESULTS: A total of 4207 subjects with cerebral vascular disease and no cognitive impairment were included, of whom 392 converted to dementia during an average 5.15-year (SD: 3.79) follow-up. Depression (Adjusted HR: 1.54, 95%CI: 1.13-2.09), osteoporosis (Adjusted HR: 1.34, 95%CI: 1.04- 1.74) and the use of enalapril (Adjusted HR: 1.37, 95%CI: 1.09-1.73) were risk factors for dementia, while nitroglycerin (Adjusted HR: 0.67, 95%CI: 0.53-0.85) was a protecting factor, in subjects with cerebrovascular diseases without mention of cerebral infarction. In total, statins were shown to be associated with decreased risk of dementia (HR:0.73, 95%CI: 0.59-0.91); however, no one statin subtype or TCM had such an effect. CONCLUSION: Depression, osteoporosis and the use of enalapril were associated with a higher risk of dementia, while nitroglycerin might be a protecting factor for dementia, in subjects with cerebrovascular diseases without mention of cerebral infarction.