Article Text

Download PDFPDF

Prevalence and determinants of undetected dementia in the community: a systematic literature review and a meta-analysis
  1. Linda Lang1,2,
  2. Angela Clifford1,
  3. Li Wei3,
  4. Dongmei Zhang4,
  5. Daryl Leung5,
  6. Glenda Augustine6,
  7. Isaac M Danat1,
  8. Weiju Zhou1,
  9. John R Copeland7,
  10. Kaarin J Anstey8,
  11. Ruoling Chen1,2
  1. 1Faculty of Education, Health and Wellbeing University of Wolverhampton, Wolverhampton, UK
  2. 2Post Graduate Academic Institute of Medicine, University of Wolverhampton, Wolverhampton, UK
  3. 3Department of Practice and Policy, University College London, London, UK
  4. 4School of Health Administration, Anhui Medical University, China
  5. 5New Cross Hospital, The Royal Wolverhampton NHS Trust, UK
  6. 6Department of Public Health, Wolverhampton City Council, Wolverhampton, UK
  7. 7Department of Psychiatry, University of Liverpool, Liverpool, UK
  8. 8Dementia Collaborative Research Centre-Early Diagnosis and Prevention, Centre for Research on Ageing, Health and Wellbeing, Research School of Population Health, The Australian National University, Canberra, Australia
  1. Correspondence to Dr Ruoling Chen, r.chen{at}; Dr Li Wei, and Dr Dongmei Zhang (for Chinese),


Objectives Detection of dementia is essential for improving the lives of patients but the extent of underdetection worldwide and its causes are not known. This study aimed to quantify the prevalence of undetected dementia and to examine its correlates.

Methods/setting/participants A systematic search was conducted until October 2016 for studies reporting the proportion of undetected dementia and/or its determinants in either the community or in residential care settings worldwide. Random-effects models calculated the pooled rate of undetected dementia and subgroup analyses were conducted to identify determinants of the variation.

Primary and secondary outcome measures The outcome measures of interest were the prevalence and determinants of undetected dementia.

Results 23 studies were eligible for inclusion in this review. The pooled rate of undetected dementia was 61.7% (95% CI 55.0% to 68.0%). The rate of underdetection was higher in China and India (vs Europe and North America), in the community setting (vs residential/nursing care), age of <70 years, male gender and diagnosis by general practitioner. However, it was lower in the studies using Mini-Mental State Examination (MMSE) diagnosis criteria.

Conclusions The prevalence of undetected dementia is high globally. Wide variations in detecting dementia need to be urgently examined, particularly in populations with low socioeconomic status. Efforts are required to reduce diagnostic inequality and to improve early diagnosis in the community.


This is an Open Access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.


  • ▸ Additional material is available. To view please visit the journal online (

  • AC is co-first author.

  • Contributors RC created a research idea for this study and made its conception and design. LL and AC were involved in the conception and design of this study, and contributed to the literature search and review. ID and WZ searched and reviewed the literature of 2013–2016. LW and DZ and RC were responsible for quantitative data analysis. JC, KJA, DL and GA contributed, along with all other authors, equally to the interpretation of the results and discussion of their implications. All authors were substantially involved in the writing and revisions of this manuscript, and all have given approval of the final version.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement No additional data are available.