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The Diagnostic Pathway From Cognitive Impairment to Dementia in Japan

Quantification Using Real-World Data

Black, Christopher M. PhD, MPH*; Ambegaonkar, Baishali M. PhD*; Pike, James MPhil; Jones, Eddie BA; Husbands, Joseph BSc; Khandker, Rezaul K. PhD, MBA*

Alzheimer Disease & Associated Disorders: October–December 2019 - Volume 33 - Issue 4 - p 346–353
doi: 10.1097/WAD.0000000000000322
Original Articles

Objective: This study aimed to quantify the diagnostic pathway from cognitive impairment (CI) to dementia in Japan.

Methods: This was a real-world, cross-sectional survey of patients with CI and their physicians.

Results: Data for 1107 patients were provided by 106 physicians. Mean time from initial symptoms to the first consultation was 7.4±6.9 months; 42% of patients had moderate/severe CI at first consultation. Mean time from the first consultation to formal diagnosis was 2.9±11.0 months (1.9±8.8 mo if not referred to a secondary physician, and 5.1±14.6 mo if referred). Time from the first consultation to diagnosis was shorter with more severe CI at first consultation (P=0.0072). The highest proportion of patients were diagnosed by neurologists (45.8%). Tests or scales were used to aid diagnosis in 81.2% of patients. There was no association of disease severity and referral to a secondary physician; 30.9% of patients were referred, the majority (57.7%) to a neurologist.

Conclusions: A substantial proportion of patients with dementia in Japan experience CI for some time before consulting a physician. Government policy to increase public understanding and awareness of dementia, and a proposed dementia screening system, should increase the proportion of individuals consulting physicians before disease progression.

*Center for Observational and Real-World Evidence, Merck & Co. Inc., Kenilworth, NJ

Adelphi Real World, Macclesfield, UK

Medical writing support under the guidance of the authors was provided by Carole Evans, PhD, on behalf of Adelphi Real World, and was funded by Merck & Co. Inc., Kenilworth, NJ, in accordance with Good Publication Practice (GPP3) guidelines (Ann Intern Med 2015;163:461–464).

C.M.B., B.M.A., and R.K.K. are employed by Merck & Co. Inc. (who funded this study) and also hold Merck & Co. Inc., Kenilworth, NJ, stocks. J.P., E.J., and J.H. are employed by Adelphi Real World.

Reprints: Christopher M. Black, PhD, MPH, Outcomes Research, Center for Observational and Real-World Evidence, Merck & Co. Inc., Kenilworth, NJ 07033 (e-mail:

Received February 5, 2019

Accepted April 2, 2019

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