Rationale and design of the Kanyini guidelines adherence with the polypill (Kanyini-GAP) study: a randomised controlled trial of a polypill-based strategy amongst indigenous and non indigenous people at high cardiovascular risk.

Hueiming Liu,Bruce Neal,Alex Brown,Andrew Tonkin,Sandra Eades,Stephen Jan,Alan Cass,Greg Stewart,Christopher Reid,Ian Ring,Anthony Rodgers,Noel Hayman,Vicki Wade,Tim Usherwood,Hugh Burke,Tarun Weeramanthri,Anushka Patel,David Peiris

doi:10.1186/1471-2458-10-458

Abstract

BackgroundThe Kanyini Guidelines Adherence with the Polypill (Kanyini-GAP) Study aims to examine whether a polypill-based strategy (using a single capsule containing aspirin, a statin and two blood pressure-lowering agents) amongst Indigenous and non-Indigenous people at high risk of experiencing a cardiovascular event will improve adherence to guideline-indicated therapies, and lower blood pressure and cholesterol levels.Methods/DesignThe study is an open, randomised, controlled, multi-centre trial involving 1000 participants at high risk of cardiovascular events recruited from mainstream general practices and Aboriginal Medical Services, followed for an average of 18 months. The participants will be randomised to one of two versions of the polypill, the version chosen by the treating health professional according to clinical features of the patient, or to usual care. The primary study outcomes will be changes, from baseline measures, in serum cholesterol and systolic blood pressure and self-reported current use of aspirin, a statin and at least two blood pressure lowering agents. Secondary study outcomes include cardiovascular events, renal outcomes, self-reported barriers to indicated therapy, prescription of indicated therapy, occurrence of serious adverse events and changes in quality-of-life. The trial will be supplemented by formal economic and process evaluations.DiscussionThe Kanyini-GAP trial will provide new evidence as to whether or not a polypill-based strategy improves adherence to effective cardiovascular medications amongst individuals in whom these treatments are indicated.Trial RegistrationThis trial is registered with the Australian New Zealand Clinical Trial Registry ACTRN126080005833347.

Highlights

The Kanyini Guidelines Adherence with the Polypill (Kanyini-GAP) Study aims to examine whether a polypill-based strategy amongst Indigenous and non-Indigenous people at high risk of experiencing a cardiovascular event will improve adherence to guideline-indicated therapies, and lower blood pressure and cholesterol levels
In Australia, this is the case for Indigenous peoples, amongst whom more than one third of the total disease burden is due to cardiovascular disease (CVD), chronic kidney disease (CKD) and diabetes[1]
The following assumptions inform sample size estimates: (i) there is 35% baseline adherence to all components of the polypill; (ii) adherence to all components of the polypill among participants randomised to “usual care” over the duration of the trial will increase to 50%; and (iii) 80% of participants randomised to the polypillbased strategy will remain adherent to the polypill during follow-up

Summary

Introduction

The Kanyini Guidelines Adherence with the Polypill (Kanyini-GAP) Study aims to examine whether a polypill-based strategy (using a single capsule containing aspirin, a statin and two blood pressure-lowering agents) amongst Indigenous and non-Indigenous people at high risk of experiencing a cardiovascular event will improve adherence to guideline-indicated therapies, and lower blood pressure and cholesterol levels. Current national guidelines for the prevention of cardiovascular events in people with established athero-thrombotic vascular disease, or at high risk of these events, recommend - unless contraindicated - aspirin, Angiotensin Converting Enzyme (ACE) inhibitors and statin therapy[2,3,4,5]. The KVC Audit showed that, amongst a random sample of 1165 Indigenous adults, 40% of patients with established CVD had not been prescribed the combination of blood pressure (BP) lowering medicines, statins and antiplatelet agents and that 56% of high risk individuals without CVD had not been prescribed BP medicines and statins[7]. Similar screening and treatment gaps were found for predominantly non-Indigenous adults in mainstream general practices[8] and in other Australian and international studies[9,10,11,12,13,14]

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