Effectiveness of blood pressure-lowering drug treatment by levels of absolute risk: Post hoc analysis of the Australian National Blood Pressure Study

Chau Le Bao Ho, Monique Breslin, Jenny Doust, Christopher M. Reid, Mark R. Nelson

Research output: Contribution to journalArticleResearchpeer-review

4 Citations (Scopus)
20 Downloads (Pure)

Abstract

Objectives In many current guidelines, blood pressure (BP)-lowering drug treatment for primary prevention of cardiovascular disease (CVD) is based on absolute risk. However, in clinical practice, therapeutic decisions are often based on BP levels alone. We sought to investigate which approach was superior by conducting a post hoc analysis of the Australian National Blood Pressure (ANBP) cohort, a seminal study establishing the efficacy of BP lowering in mild hypertensive' persons. Design A post hoc subgroup analysis of the ANBP trial results by baseline absolute risk tertile. Setting and participants 3244 participants aged 35-69 years in a community-based randomised placebo controlled trial of blood pressure-lowering medication. Interventions Chlorothiazide500 mg versus placebo. Primary outcome measures All-cause mortality and non-fatal events (non-fatal CVD, congestive cardiac failure, renal failure, hypertensive retinopathy or encephalopathy). Results Treatment effects were assessed by HR, absolute risk reduction and number needed to treat. Participants had an average 5-year CVD risk in the intermediate range (10.5±6.5) with moderately elevated BP (mean 159/103 mmHg) and were middle aged (52±8 years). In a subgroup analysis, the relative effects (HR) and absolute effects (absolute risk reduction and number needed to treat) did not statistically differ across the three risk groups except for the absolute benefit in all-cause mortality (p for heterogeneity=0.04). With respect to absolute benefit, drug treatment significantly reduced the number of events in the high-risk group regarding any event with a number needed to treat of 18 (10 to 64), death from any cause with 45 (25 to 196) and major CVD events with 23 (12 to 193). Conclusion Our analysis confirms that the benefit of treatment was substantial only in the high-risk tertile, reaffirming the rationale of treating elevated blood pressure in the setting of all risk factors rather than in isolation.

Original languageEnglish
Article numbere017723
JournalBMJ Open
Volume8
Issue number3
DOIs
Publication statusPublished - 1 Mar 2018

Fingerprint

Numbers Needed To Treat
Blood Pressure
Pharmaceutical Preparations
Cardiovascular Diseases
Therapeutics
Hypertensive Retinopathy
Hypertensive Encephalopathy
Placebos
Mortality
Primary Prevention
Renal Insufficiency
Cause of Death
Randomized Controlled Trials
Heart Failure
Outcome Assessment (Health Care)
Guidelines

Cite this

@article{c1f6b4098c434f6292505df40af6916c,
title = "Effectiveness of blood pressure-lowering drug treatment by levels of absolute risk: Post hoc analysis of the Australian National Blood Pressure Study",
abstract = "Objectives In many current guidelines, blood pressure (BP)-lowering drug treatment for primary prevention of cardiovascular disease (CVD) is based on absolute risk. However, in clinical practice, therapeutic decisions are often based on BP levels alone. We sought to investigate which approach was superior by conducting a post hoc analysis of the Australian National Blood Pressure (ANBP) cohort, a seminal study establishing the efficacy of BP lowering in mild hypertensive' persons. Design A post hoc subgroup analysis of the ANBP trial results by baseline absolute risk tertile. Setting and participants 3244 participants aged 35-69 years in a community-based randomised placebo controlled trial of blood pressure-lowering medication. Interventions Chlorothiazide500 mg versus placebo. Primary outcome measures All-cause mortality and non-fatal events (non-fatal CVD, congestive cardiac failure, renal failure, hypertensive retinopathy or encephalopathy). Results Treatment effects were assessed by HR, absolute risk reduction and number needed to treat. Participants had an average 5-year CVD risk in the intermediate range (10.5±6.5) with moderately elevated BP (mean 159/103 mmHg) and were middle aged (52±8 years). In a subgroup analysis, the relative effects (HR) and absolute effects (absolute risk reduction and number needed to treat) did not statistically differ across the three risk groups except for the absolute benefit in all-cause mortality (p for heterogeneity=0.04). With respect to absolute benefit, drug treatment significantly reduced the number of events in the high-risk group regarding any event with a number needed to treat of 18 (10 to 64), death from any cause with 45 (25 to 196) and major CVD events with 23 (12 to 193). Conclusion Our analysis confirms that the benefit of treatment was substantial only in the high-risk tertile, reaffirming the rationale of treating elevated blood pressure in the setting of all risk factors rather than in isolation.",
author = "Ho, {Chau Le Bao} and Monique Breslin and Jenny Doust and Reid, {Christopher M.} and Nelson, {Mark R.}",
year = "2018",
month = "3",
day = "1",
doi = "10.1136/bmjopen-2017-017723",
language = "English",
volume = "8",
journal = "BMJ Open",
issn = "2044-6055",
publisher = "BMJ Publishing Group",
number = "3",

}

Effectiveness of blood pressure-lowering drug treatment by levels of absolute risk : Post hoc analysis of the Australian National Blood Pressure Study. / Ho, Chau Le Bao; Breslin, Monique; Doust, Jenny; Reid, Christopher M.; Nelson, Mark R.

In: BMJ Open, Vol. 8, No. 3, e017723, 01.03.2018.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Effectiveness of blood pressure-lowering drug treatment by levels of absolute risk

T2 - Post hoc analysis of the Australian National Blood Pressure Study

AU - Ho, Chau Le Bao

AU - Breslin, Monique

AU - Doust, Jenny

AU - Reid, Christopher M.

AU - Nelson, Mark R.

PY - 2018/3/1

Y1 - 2018/3/1

N2 - Objectives In many current guidelines, blood pressure (BP)-lowering drug treatment for primary prevention of cardiovascular disease (CVD) is based on absolute risk. However, in clinical practice, therapeutic decisions are often based on BP levels alone. We sought to investigate which approach was superior by conducting a post hoc analysis of the Australian National Blood Pressure (ANBP) cohort, a seminal study establishing the efficacy of BP lowering in mild hypertensive' persons. Design A post hoc subgroup analysis of the ANBP trial results by baseline absolute risk tertile. Setting and participants 3244 participants aged 35-69 years in a community-based randomised placebo controlled trial of blood pressure-lowering medication. Interventions Chlorothiazide500 mg versus placebo. Primary outcome measures All-cause mortality and non-fatal events (non-fatal CVD, congestive cardiac failure, renal failure, hypertensive retinopathy or encephalopathy). Results Treatment effects were assessed by HR, absolute risk reduction and number needed to treat. Participants had an average 5-year CVD risk in the intermediate range (10.5±6.5) with moderately elevated BP (mean 159/103 mmHg) and were middle aged (52±8 years). In a subgroup analysis, the relative effects (HR) and absolute effects (absolute risk reduction and number needed to treat) did not statistically differ across the three risk groups except for the absolute benefit in all-cause mortality (p for heterogeneity=0.04). With respect to absolute benefit, drug treatment significantly reduced the number of events in the high-risk group regarding any event with a number needed to treat of 18 (10 to 64), death from any cause with 45 (25 to 196) and major CVD events with 23 (12 to 193). Conclusion Our analysis confirms that the benefit of treatment was substantial only in the high-risk tertile, reaffirming the rationale of treating elevated blood pressure in the setting of all risk factors rather than in isolation.

AB - Objectives In many current guidelines, blood pressure (BP)-lowering drug treatment for primary prevention of cardiovascular disease (CVD) is based on absolute risk. However, in clinical practice, therapeutic decisions are often based on BP levels alone. We sought to investigate which approach was superior by conducting a post hoc analysis of the Australian National Blood Pressure (ANBP) cohort, a seminal study establishing the efficacy of BP lowering in mild hypertensive' persons. Design A post hoc subgroup analysis of the ANBP trial results by baseline absolute risk tertile. Setting and participants 3244 participants aged 35-69 years in a community-based randomised placebo controlled trial of blood pressure-lowering medication. Interventions Chlorothiazide500 mg versus placebo. Primary outcome measures All-cause mortality and non-fatal events (non-fatal CVD, congestive cardiac failure, renal failure, hypertensive retinopathy or encephalopathy). Results Treatment effects were assessed by HR, absolute risk reduction and number needed to treat. Participants had an average 5-year CVD risk in the intermediate range (10.5±6.5) with moderately elevated BP (mean 159/103 mmHg) and were middle aged (52±8 years). In a subgroup analysis, the relative effects (HR) and absolute effects (absolute risk reduction and number needed to treat) did not statistically differ across the three risk groups except for the absolute benefit in all-cause mortality (p for heterogeneity=0.04). With respect to absolute benefit, drug treatment significantly reduced the number of events in the high-risk group regarding any event with a number needed to treat of 18 (10 to 64), death from any cause with 45 (25 to 196) and major CVD events with 23 (12 to 193). Conclusion Our analysis confirms that the benefit of treatment was substantial only in the high-risk tertile, reaffirming the rationale of treating elevated blood pressure in the setting of all risk factors rather than in isolation.

UR - http://www.scopus.com/inward/record.url?scp=85044195058&partnerID=8YFLogxK

U2 - 10.1136/bmjopen-2017-017723

DO - 10.1136/bmjopen-2017-017723

M3 - Article

VL - 8

JO - BMJ Open

JF - BMJ Open

SN - 2044-6055

IS - 3

M1 - e017723

ER -