Hormone replacement therapy and dementia risk: nested case-control studies using CPRD and QResearch

Vinogradova, Yana; Dening, Tom; Hippisley-Cox, Julia; Taylor, Lauren; Moore, Michael; Coupland, Carol

Abstract

Introduction: Research from clinical trials of hormone replacement therapy (HRT) has produced conflicting findings about possible risks of dementia after receiving these treatments, and further research on HRT and dementia risk has been identified as a priority. This study will investigate risks of incident dementia associated with different types of hormone replacement therapy (HRT), using data from two primary care databases (CPRD and QResearch).

Method: The study design is two nested case-control studies, one in each database. Cases will be women aged 55 years and over with incident dementia diagnosed between 1998 and 2020, matched with up to 5 controls by age, practice and calendar year. Cases of dementia will be identified in each database using general practice clinical and other linked data. The outcome for analysis is incident dementia. The exposure will be having received prescriptions for HRT.

Analysis: Exposure to different HRT treatments will be defined as at least one prescription for that treatment excluding the three years prior to the index date (date of diagnosis of dementia or equivalent date in matched controls). Conditional logistic regression will be used to assess the risks associated with different types of oestrogen and progestogen. The effects of duration, length of any gap since the last use, different application routes and the age at which treatment started will be analysed for the most common types of hormones used. All analyses will be adjusted by available data for potential confounding variables.

Analysis using this same protocol will be carried out using data from each of two primary care databases (CPRD and QResearch). Adjusted odds ratios from the conditional regression analyses of the two datasets will be pooled using a fixed effect model with inverse variance weights.

Discussion: The study findings will show whether receipt of HRT is associated with either an increased or decreased risk of subsequent incident dementia. These results will inform future national and international guidance for women and for prescribers.

Citation

Vinogradova, Y., Dening, T., Hippisley-Cox, J., Taylor, L., Moore, M., & Coupland, C. (2021). Hormone replacement therapy and dementia risk: nested case-control studies using CPRD and QResearch. East Midlands Research into Ageing Network (EMRAN) Discussion Paper Series, 38, 1-16

• Journal Article Type: Article
• Acceptance Date: Feb 26, 2021
• Online Publication Date: Feb 26, 2021
• Publication Date: Feb 26, 2021
• Deposit Date: Apr 19, 2021
• Publicly Available Date: Apr 29, 2021
• Journal: East Midlands Research into Ageing Network (EMRAN) Discussion Paper Series
• Electronic ISSN: 2059-3341
• Publisher: East Midlands Research into Ageing Network
• Peer Reviewed: Peer Reviewed
• Volume: 38
• Pages: 1-16
• Keywords: Hormone replacement therapy, dementia, incidence, risk, primary care
• Public URL: https://nottingham-repository.worktribe.com/output/5482691
• Publisher URL: https://www.nottingham.ac.uk/emran/documents/issue38-emran-04mar2021-vinogradova-y.pdf
• Related Public URLs: https://www.nottingham.ac.uk/emran/
• Additional Information: East Midlands Research into Ageing Network (EMRAN) is a research collaboration across the East Midlands to facilitate applied research into ageing and the care of older people. EMRAN was set up with support from National Institute of Health Research Applied Research Collaboration East Midlands (NIHR ARC-EM).