title: Forecasting the Incidence of Dementia and Dementia-Related Outpatient Visits With Google Trends: Evidence From Taiwan.
abstract: BACKGROUND
  Google Trends has demonstrated the capability to both monitor and predict epidemic outbreaks. The connection between Internet searches for dementia information and dementia incidence and dementia-related outpatient visits remains unknown.
  
  
  OBJECTIVE
  This study aimed to determine whether Google Trends could provide insight into trends in dementia incidence and related outpatient visits in Taiwan. We investigated and validated the local search terms that would be the best predictors of new dementia cases and outpatient visits. We further evaluated the nowcasting (ie, forecasting the present) and forecasting effects of Google Trends search trends for new dementia cases and outpatient visits. The long-term goal is to develop a surveillance system to help early detection and interventions for dementia in Taiwan.
  
  
  METHODS
  This study collected (1) dementia data from Taiwan's National Health Insurance Research Database and (2) local Internet search data from Google Trends, both from January 2009 to December 2011. We investigated and validated search terms that would be the best predictors of new dementia cases and outpatient visits. We then evaluated both the nowcasting and the forecasting effects of Google Trends search trends through cross-correlation analysis of the dementia incidence and outpatient visit data with the Google Trends data.
  
  
  RESULTS
  The search term "dementia + Alzheimer's disease" demonstrated a 3-month lead effect for new dementia cases and a 6-month lead effect for outpatient visits (r=.503, P=.002; r=.431, P=.009, respectively). When gender was included in the analysis, the search term "dementia" showed 6-month predictive power for new female dementia cases (r=.520, P=.001), but only a nowcasting effect for male cases (r=.430, P=.009). The search term "neurology" demonstrated a 3-month leading effect for new dementia cases (r=.433, P=.008), for new male dementia cases (r=.434, P=.008), and for outpatient visits (r=.613, P<.001).
  
  
  CONCLUSIONS
  Google Trends established a plausible relationship between search terms and new dementia cases and dementia-related outpatient visits in Taiwan. This data may allow the health care system in Taiwan to prepare for upcoming outpatient and dementia screening visits. In addition, the validated search term results can be used to provide caregivers with caregiving-related health, skills, and social welfare information by embedding dementia-related search keywords in relevant online articles.
authors.affiliation: Institute of Health Policy and Management, National Taiwan University, Taipei, Taiwan.
authors.forename: Ho-Wei
authors.identifier: http://orcid.org/0000-0003-3394-1782
authors.initials: HW
authors.lastname: Wang
authors.forename: Duan-Rung
authors.identifier: http://orcid.org/0000-0002-6391-987X
authors.initials: DR
authors.lastname: Chen
authors.forename: Hsiao-Wei
authors.identifier: http://orcid.org/0000-0002-6668-7971
authors.initials: HW
authors.lastname: Yu
authors.forename: Ya-Mei
authors.identifier: http://orcid.org/0000-0003-0378-9441
authors.initials: YM
authors.lastname: Chen
mesh_terms: D003704:Dementia / Q000453:epidemiology*; D005260:Female; D006801:Humans; D015994:Incidence; D020407:Internet / Q000706:statistics & numerical data / Q000639:trends*; D008297:Male; D010045:Outpatients; D013624:Taiwan
keywords: Alzheimer’s disease; Google Trends; Internet search; big data; dementia; early detection; health-seeking behaviors; incidence; self-diagnosis