Dementia undetected or undiagnosed in primary care: the prevalence, causes and consequences.
Early recognition of dementia with 67 percent of cases diagnosed is an aim of NHS England. To achieve this, incentives, education and specialist clinics have been introduced to promote dementia recognition and diagnosis in primary care. However, the process of diagnosis is often delayed, protracted or complicated and a significant proportion of people do not appear to receive diagnosis. Understanding the factors underlying this using robust research data could help us improve people’s access to timely diagnosis. In order to determine the true prevalence of dementia or correlates of dementia not known to primary care it is necessary for diagnoses made in primary care to be linked to independent and objective dementia diagnoses at the patient level.
The Cognitive Function and Ageing Study II (CFAS II) Dementia Diagnosis Study (CADDY) which aims to determine prevalence, causes and consequences of undiagnosed dementia is a sub-study of CFAS II. During 2008-2011 CFAS II recruited a population-representative sample of 7500 people aged 65 and older from three geographical areas of England. Knowledgeable informants were also recruited for a subsample of participants. Participants completed detailed cognitive, health and socioeconomic assessments. They were conducted by trained researchers at baseline and at two-year follow up assessment. For each participant a study dementia status, previously validated against DMS-III-R, was established. Under CADDY, primary care records were sought for 598 CFAS II participants consenting to health service data linkage (445 with a CFAS II diagnosis of dementia and 153 without dementia but weighted toward those with cognitive impairment). Dementia diagnoses, cognitive complaint and referrals to specialist services were extracted from primary care records and these data were linked with CFASII data. Linking CFASII assessments and diagnoses with records held in primary care provides a rare opportunity to estimate: (i) the true proportion of people with dementia with a formal diagnosis; (ii) social and clinical predictors of becoming diagnosed; and (iii) outcomes among diagnosed and non-diagnosed populations. Hypothesised predictors include social circumstances, severity of cognitive and behavioural symptoms, comorbidities and service use outcomes.
To date, 509 (85%) primary care records have been returned. We will present the prevalence of diagnosis within primary care with respect to dementia severity, recorded help-seeking or referral to secondary services, and compare the characteristics and levels of service use for diagnosed and undiagnosed people with dementia.
Epidemiological studies including objective validated dementia diagnoses provide a unique opportunity to estimate the extent and predictors of diagnosis and health service use among people with dementia. This study is important to understanding dementia in populations, estimating the true proportion of people with dementia with a formal diagnosis, and informing policy initiatives to enable effective targeting of diagnostic and support services.