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The risk of all-cause and cause-specific mortality in people prescribed mirtazapine: an active comparator cohort study using electronic health records

Joseph, Rebecca M.; Jack, Ruth H.; Morriss, Richard; Knaggs, Roger David; Butler, Debbie; Hollis, Chris; Hippisley-Cox, Julia; Coupland, Carol

The risk of all-cause and cause-specific mortality in people prescribed mirtazapine: an active comparator cohort study using electronic health records Thumbnail


Authors

Rebecca M. Joseph

RUTH JACK Ruth.Jack@nottingham.ac.uk
Senior Research Fellow

RICHARD MORRISS richard.morriss@nottingham.ac.uk
Professor of Psychiatry and Community Mental Health

Debbie Butler

CHRIS HOLLIS chris.hollis@nottingham.ac.uk
Professor of Child and Adolescent Psychiatry and Digital Mental Health

Julia Hippisley-Cox

CAROL COUPLAND carol.coupland@nottingham.ac.uk
Professor of Medical Statistics



Abstract

Background
Studies have reported an increased risk of mortality among people prescribed mirtazapine compared to other antidepressants. The study aimed to compare all-cause and cause-specific mortality between adults prescribed mirtazapine or other second-line antidepressants.

Methods
This cohort study used English primary care electronic medical records, hospital admission records, and mortality data from the Clinical Practice Research Datalink (CPRD), for the period 01 January 2005 to 30 November 2018. It included people aged 18-99 years with depression first prescribed a selective serotonin reuptake inhibitor (SSRI) and then prescribed mirtazapine (5,081), a different SSRI (15,032), amitriptyline (3,905), or venlafaxine (1,580). Follow-up was from starting to stopping the second antidepressant, with a 6-month wash-out window, censoring at the end of CPRD follow-up or 30 November 2018. Age-sex standardised rates of all-cause mortality and death due to circulatory system disease, cancer, or respiratory system disease were calculated. Survival analyses were performed, accounting for baseline characteristics using inverse probability of treatment weighting.

Results
The cohort contained 25,598 people (median age 41 years). The mirtazapine group had the highest standardised mortality rate, with an additional 7.8 (95% confidence interval (CI) 5.9-9.7) deaths/1000 person-years compared to the SSRI group. Within two years of follow-up, the risk of all-cause mortality was statistically significantly higher in the mirtazapine group than the SSRI group (weighted hazard ratio (HR) 1.62, 95% CI 1.28-2.06). No significant difference was found between the mirtazapine group and the amitriptyline (HR 1.18, 95% CI 0.85-1.63) or venlafaxine (HR 1.11, 95% CI 0.60-2.05) groups. After two years, the risk was significantly higher in the mirtazapine group compared to the SSRI (HR 1.51, 95% CI 1.04-2.19), amitriptyline (HR 2.59, 95% CI 1.38-4.86), and venlafaxine (HR 2.35, 95% CI 1.02-5.44) groups. The risks of death due to cancer (HR 1.74, 95% CI 1.06-2.85) and respiratory system disease (HR 1.72, 95% CI 1.07- 2.77) were significantly higher in the mirtazapine than the SSRI group.

Conclusions
Mortality was higher in people prescribed mirtazapine than people prescribed a second SSRI, possibly reflecting residual differences in other risk factors between groups. Identifying these potential health risks when prescribing mirtazapine may help reduce the risk of mortality.

Citation

Joseph, R. M., Jack, R. H., Morriss, R., Knaggs, R. D., Butler, D., Hollis, C., …Coupland, C. (2022). The risk of all-cause and cause-specific mortality in people prescribed mirtazapine: an active comparator cohort study using electronic health records. BMC Medicine, 20(1), Article 43. https://doi.org/10.1186/s12916-022-02247-x

Journal Article Type Article
Acceptance Date Jan 10, 2022
Online Publication Date Feb 2, 2022
Publication Date Feb 2, 2022
Deposit Date Jan 26, 2022
Publicly Available Date Mar 29, 2024
Journal BMC Medicine
Electronic ISSN 1741-7015
Publisher Springer Science and Business Media LLC
Peer Reviewed Peer Reviewed
Volume 20
Issue 1
Article Number 43
DOI https://doi.org/10.1186/s12916-022-02247-x
Keywords General Medicine
Public URL https://nottingham-repository.worktribe.com/output/7340212
Publisher URL https://bmcmedicine.biomedcentral.com/articles/10.1186/s12916-022-02247-x