The design of an observational study of hypertension management, adherence and pressure control in Blood Pressure Success Zone Program participants

K A Payne,K J Ishak,J J Caro,W L Daley,E Velázquez,Z M Khan,J Flack,S Nesbitt,K Stark,For The Bpsz-Bliss Study Steering Committee ,R Califf,D Purkayastha,D Morisky

doi:10.1111/j.1742-1241.2008.01840.x

Abstract

AimsThe Blood Pressure Success Zone (BPSZ) Program, a nationwide initiative, provides education in addition to a complimentary trial of one of three antihypertensive medications. The BPSZ Longitudinal Observational Study of Success (BPSZ-BLISS) aims to evaluate blood pressure (BP) control, adherence, persistence and patient satisfaction in a representative subset of BPSZ Program participants. The BPSZ-BLISS study design is described here.MethodsA total of 20,000 physicians were invited to participate in the study. Using a call centre supported Interactive Voice Response System (IVRS), physicians report BP and other data at enrolment and every usual care visit up to 12 ± 2 months; subjects self-report BPs, persistence, adherence and treatment satisfaction at 3, 6 and 12 months post-BPSZ Program enrolment. In addition to BPSZ Program enrolment medications, physicians prescribe antihypertensive medications and schedule visits as per usual care. The General Electric Healthcare database will be used as an external reference.ResultsAfter 18 months, over 700 IRB approved physicians consented and enrolled 10,067 eligible subjects (48% male; mean age 56 years; 27% newly diagnosed); 97% of physicians and 78% of subjects successfully entered IVRS enrolment data. Automated IVRS validations have maintained data quality (< 5% error on key variables). Enrolment was closed 30 April 2007; study completion is scheduled for June 2008.ConclusionsThe evaluation of large-scale health education programmes requires innovative methodologies and data management and quality control processes. The BPSZ-BLISS design can provide insights into the conceptualisation and planning of similar studies.

Highlights

Despite an abundance of antihypertensive medications with proven efficacy, up to two-thirds of treated hypertensive patients do not achieve blood pressure (BP) control [1,2]
Given the cost and the medical implications associated with uncontrolled BP, the US government has embarked on a national initiative (2010 initiative) to control 50% of treated hypertensive patients by the year 2010 [19]
Patients must be new to the programme and have either a new diagnosis of hypertension, or an established diagnosis of hypertension that is uncontrolled on antihypertensive medication

Summary

Introduction

Despite an abundance of antihypertensive medications with proven efficacy, up to two-thirds of treated hypertensive patients do not achieve blood pressure (BP) control [1,2]. The failure to take medications according to the prescribed regimen (nonadherence), and even worse, the discontinuation of treatment (non-persistence) are the main factors contributing to this problem [3,4,5,6,7,8,9]. Failure to control hypertension in the USA has been estimated to cost US $467 million among treated patients and US $964 million if both treated and untreated are considered [16]. In Canada [17] and the USA [18], the estimated average annual medical cost per patient for the treatment of hypertension is approximately $4000 USD. Given the cost and the medical implications associated with uncontrolled BP, the US government has embarked on a national initiative (2010 initiative) to control 50% of treated hypertensive patients by the year 2010 [19]

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