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Research article:

Are primary care consultations for insomnia associated with subsequent onset of dementia? A matched retrospective case-control study


Richard Hoile, Naji Tabet, Helen Smith, Stephen Bremner, Jackie Cassell, Elizabeth Ford(2017) Are primary care consultations for insomnia associated with subsequent onset of dementia? A matched retrospective case-control study. , doi:

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Background Insomnia is associated with dementia, but whether insomnia is merely a symptom of dementia, or an early prodrome or causative factor, is unclear. We investigated the association between primary care consultations for insomnia and later development of dementia. Methods A case-control study, using primary care records for 30418 patients from the UK’s Clinical Practice Research Datalink. Cases (with dementia) and controls (without) were matched 1:1 on year of birth and gender. Primary care insomnia consultations were measured during the period 5-10 years before the index date. Adjusted odds ratios (aOR) for developing dementia were estimated with 95% confidence intervals (CIs) using logistic regression, after controlling for sedative exposure (including antipsychotics, benzodiazepines and z-drugs) and physical and mental health comorbidities. Results The adjusted odds ratio (aOR) for dementia was 1.31 (95% CI=1.18-1.45, p<0.01) in those with at least one insomnia consultation 5-10 years prior to index date; and 1.90 (95% CI=1.14-3.17, p=0.01) for those with more than 5 consultations. There was a significant but weak association between dementia and benzodiazepine/z-drug use (aOR 1.01, 95% CI=1.00-1.01, p<0.01). Conclusion This case-control study provides evidence of an association between insomnia consultations and onset of dementia 5-10 years later. It may be possible to incorporate insomnia into future screening and predictive tools for dementia, especially those used in primary care.
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Richard Hoile
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Res27: Chronic pulmonary disease Download this codelist
Res43: hf_kontopantelis_bmjqs2012 Download this codelist
Res60: stroke Download this codelist
Res60: insomnia Download this codelist
Res60: sleep_apnoea Download this codelist
Res60: Mental illness Download this codelist
Res60: Alzheimers-vascular-non-specific dementia Download this codelist

2 comments have been posted.

Sept. 24, 2017, 2:35 p.m. - Richard Hoile

All code lists starting 'Res60' were created by ourselves especially for this study (or adapted from existing code lists used in other ClinicalCodes studies). Code lists not starting 'Res60' have been borrowed unaltered from other studies.

Aug. 23, 2018, 9:51 a.m. - Richard Hoile

Res43: hf_kontopantelis_bmjqs2012 is a heart failure code list

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