Zhao, Yuejen; Jeyaraman K; Burgess, Paul; Connors, Christine; Guthridge S; Maple-Brown, Louise; Falhammar H

Author(s)

Zhao, Yuejen

Jeyaraman K

Burgess, Paul

Connors, Christine

Guthridge S

Maple-Brown, Louise

Falhammar H

Publication Date

2020-01-02

Abstract

To evaluate the benefit and risk of low-dose acetylsalicylic acid (aspirin) in patients from remote Aboriginal communities in the Northern Territory, Australia. Retrospective cohort study using primary care and hospital data routinely used for healthcare. Aspirin users and non-users were compared before and after controlling confounders by matching. Marginal structural models (MSM) were applied to ascertain the benefit and risk. The benefit and harm of aspirin were investigated in patients aged ≥18 years from 54 remote Aboriginal communities. None had a previous cardiovascular event or major bleeds. Patients on anticoagulants or other antiplatelets were excluded. Aspirin at a dose of 75-162 mg/day. Endpoints were all-cause, cardiovascular mortality and incidences of cardiovascular events and major bleeds. 8167 predominantly Aboriginal adults were included and followed between July 2009 and June 2017 (aspirin users n=1865, non-users n=6302, mean follow-up 4 years with hospitalisations 6.4 per person). Univariate analysis found material differences in demographics, prevalence of chronic diseases and outcome measures between aspirin users and non-users before matching. After matching, aspirin was significantly associated with reduced all-cause mortality (HR=0.45: 95% CI 0.34 to 0.60; p<0.001), but not bleeding (HR=1.13: 95% CI 0.39 to 3.26; p=0.820). After using MSMs to eliminate the effects of confounders, loss of follow-up and time dependency of treatment, aspirin was associated with reduced all-cause mortality (HR=0.60: 95% CI 0.47 to 0.76; p<0.001), independent of age (HR=1.06; p<0.001), presence of diabetes (HR=1.42; p<0.001), hypertension (HR=1.61; p<0.001) and alcohol abuse (HR=1.81; p<0.001). No association between aspirin and major bleeding was found (HR=1.14: 95% CI 0.48 to 2.73; p=0.765). Sensitivity analysis suggested these findings were unlikely to have been the result of unmeasured confounding. Aspirin was associated with reduced all-cause mortality. Bleeding risk was less compared with survival benefits. Aspirin should be considered for primary prevention in Aboriginal people with high cardiovascular risk.

Citation

BMJ open 2020-01-02; 10(1): e030034

OrcId

http://orcid.org/0000-0002-5622-6987

Pubmed ID

https://pubmed.ncbi.nlm.nih.gov/31900264/?otool=iaurydwlib

Link

https://hdl.handle.net/10137/7987

Subject

acetylsalicylic acid

coarsened exact matching

marginal structural models

propensity score matching

risk-benefit assessment

Title

All-cause mortality following low-dose aspirin treatment for patients with high cardiovascular risk in remote Australian Aboriginal communities: an observational study.

Type of document

Journal Article

Entity Type

Publication

Author(s)	Zhao, Yuejen Jeyaraman K Burgess, Paul Connors, Christine Guthridge S Maple-Brown, Louise Falhammar H
Publication Date	2020-01-02
Abstract	To evaluate the benefit and risk of low-dose acetylsalicylic acid (aspirin) in patients from remote Aboriginal communities in the Northern Territory, Australia. Retrospective cohort study using primary care and hospital data routinely used for healthcare. Aspirin users and non-users were compared before and after controlling confounders by matching. Marginal structural models (MSM) were applied to ascertain the benefit and risk. The benefit and harm of aspirin were investigated in patients aged ≥18 years from 54 remote Aboriginal communities. None had a previous cardiovascular event or major bleeds. Patients on anticoagulants or other antiplatelets were excluded. Aspirin at a dose of 75-162 mg/day. Endpoints were all-cause, cardiovascular mortality and incidences of cardiovascular events and major bleeds. 8167 predominantly Aboriginal adults were included and followed between July 2009 and June 2017 (aspirin users n=1865, non-users n=6302, mean follow-up 4 years with hospitalisations 6.4 per person). Univariate analysis found material differences in demographics, prevalence of chronic diseases and outcome measures between aspirin users and non-users before matching. After matching, aspirin was significantly associated with reduced all-cause mortality (HR=0.45: 95% CI 0.34 to 0.60; p<0.001), but not bleeding (HR=1.13: 95% CI 0.39 to 3.26; p=0.820). After using MSMs to eliminate the effects of confounders, loss of follow-up and time dependency of treatment, aspirin was associated with reduced all-cause mortality (HR=0.60: 95% CI 0.47 to 0.76; p<0.001), independent of age (HR=1.06; p<0.001), presence of diabetes (HR=1.42; p<0.001), hypertension (HR=1.61; p<0.001) and alcohol abuse (HR=1.81; p<0.001). No association between aspirin and major bleeding was found (HR=1.14: 95% CI 0.48 to 2.73; p=0.765). Sensitivity analysis suggested these findings were unlikely to have been the result of unmeasured confounding. Aspirin was associated with reduced all-cause mortality. Bleeding risk was less compared with survival benefits. Aspirin should be considered for primary prevention in Aboriginal people with high cardiovascular risk.
Citation	BMJ open 2020-01-02; 10(1): e030034
OrcId	http://orcid.org/0000-0002-5622-6987
Pubmed ID	https://pubmed.ncbi.nlm.nih.gov/31900264/?otool=iaurydwlib
Link	https://hdl.handle.net/10137/7987
Subject	acetylsalicylic acid coarsened exact matching marginal structural models propensity score matching risk-benefit assessment
Title	All-cause mortality following low-dose aspirin treatment for patients with high cardiovascular risk in remote Australian Aboriginal communities: an observational study.
Type of document	Journal Article
Entity Type	Publication

All-cause mortality following low-dose aspirin treatment for patients with high cardiovascular risk in remote Australian Aboriginal communities: an observational study.

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