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Survival of people with clinical diagnosis of dementia in primary care: cohort study

BMJ 2010; 341 doi: https://doi.org/10.1136/bmj.c3584 (Published 05 August 2010) Cite this as: BMJ 2010;341:c3584
  1. Greta Rait, senior clinical scientist1,
  2. Kate Walters, senior lecturer in primary care2,
  3. Christian Bottomley, statistician2,
  4. Irene Petersen, Medical Research Council special training fellow in health services research2,
  5. Steve Iliffe, professor of primary care for older people2,
  6. Irwin Nazareth, director1
  1. 1Medical Research Council General Practice Research Framework, London NW1 2ND
  2. 2Research Department of Primary Care and Population Health, UCL Medical School, Royal Free Campus, London NW3 2PF
  1. Correspondence to: G Rait gr{at}gprf.mrc.ac.uk
  • Accepted 21 May 2010

Abstract

Objectives To estimate survival after a diagnosis of dementia in primary care, compared with people without dementia, and to determine incidence of dementia.

Design Cohort study using data from The Health Improvement Network (THIN), a primary care database.

Setting 353 general practices in the United Kingdom providing data to THIN.

Participants All adults aged 60 years or over with a first ever code for dementia from 1990 to 2007 (n=22 529); random sample of five participants without dementia for every participant with dementia matched on practice and time period (n=112 645).

Main outcome measures Median survival by age and sex; mortality rates; incidence of dementia by age, sex, and deprivation.

Results The median survival of people with dementia diagnosed at age 60-69 was 6.7 (interquartile range 3.1-10.8) years, falling to 1.9 (0.7-3.6) years for those diagnosed at age 90 or over. Adjusted mortality rates were highest in the first year after diagnosis (relative risk 3.68, 95% confidence interval 3.44 to 3.94). This dropped to 2.49 (2.29 to 2.71) in the second year. The incidence of recorded dementia remained stable over time (3-4/1000 person years at risk). The incidence was higher in women and in younger age groups (60-79 years) living in deprived areas.

Conclusions Median survival was much lower than in screened populations. These clinically relevant estimates can assist patients and carers, clinicians, and policy makers when planning support for this population. The high risk of death in the first year after diagnosis may reflect diagnoses made at times of crisis or late in the disease trajectory. Late recording of diagnoses of dementia in primary care may result in missed opportunities for potential early interventions.

Footnotes

  • Contributors: GR, KW, IP, IN, and SI conceived the study and obtained funding. All authors were involved in the design of the study and data interpretation. CB analysed the data, and GR drafted the article. All authors participated in revising it and approved the final version. GR is the guarantor.

  • Funding: The Research Department of Primary Care and Population Health, University College London (UCL), holds a license to analyse data from THIN. This study was funded by the North Central London Research Consortium and sponsored by UCL. These sources were not involved in the analysis, interpretation, or decision to submit for publication. KW and IP were supported by a special training fellowship in health services research from the Medical Research Council (UK). This sponsor had no involvement in the analysis, interpretation, or decision to submit for publication.

  • Competing interests: None declared.

  • Ethical approval: The study was given a favourable opinion by the Cambridge 4 Research Ethics Committee (07/MRE05/30).

  • Data sharing: Lists of Read codes used are available from the corresponding author at gr{at}gprf.mrc.ac.uk.

  • Accepted 21 May 2010

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