HSR&D Home » Research » IIR 07-145 – HSR&D Study
Trial of Low And High Intensity Strategies to Maintain Blood Pressure Control
Gary E. Rosenthal, MD
Iowa City VA Health Care System, Iowa City, IA
Iowa City, IA
Funding Period: October 2008 - December 2013
In recent years, multidisciplinary strategies, based on the Chronic Care Model, have been used to overcome barriers to the treatment of hypertension (HTN) and other chronic illnesses. One such model recommended by VA / DoD HTN guidelines note is management by a pharmacist to achieve BP control goals. However, while pharmacist models of BP control have been shown to be efficacious, studies are limited by small samples and short follow-up (typically 6-12 months). Most importantly, once BP is controlled with such models, current guidelines do not provide recommendations on sustaining long-term BP control.
A major gap in our understanding is how to best sustain the effects of interventions to improve BP control and whether continued intensive interventions are needed or whether patients can be returned to primary care after an initial intervention. The three aims of this study were to:
1) Compare changes in BP in patients randomized to a long-term pharmacist intervention after an initial 6-month intervention or to a one-time education intervention after the initial 6-month intervention;
2) Compare antihypertensive medication intensification in the two groups; and
3) Compare medication adherence in the two groups.
This four-year randomized controlled trial was conducted at the Iowa City VA Health Care System and two community-based clinics. Patients were eligible if they were enrolled in primary care, had a diagnosis of HTN, and had elevated BP ( 140/90 mm Hg among nondiabetics or 140/80 mm Hg among diabetics) during their most recent VA clinic visit or based on the average from the last 3 visits. Eligible patients were enrolled and informed consent obtained if they did not have any exclusion criteria (e.g., dementia, left ventricular ejection fraction less than 35%, renal insufficiency, cirrhosis). Enrolled patients were subsequently excluded if their BP was not elevated BP during a baseline measurement by the research team. All patients received a 6-month high intensity pharmacist intervention. Following this period, the study randomized patients to a continued high intensity pharmacist intervention or to a one-time low intensity education intervention. Randomization was stratified according to whether BP was controlled after the 6-month intervention. Patients were followed for an additional 24 months. The high intensity intervention had several components, including: 1) comprehensive medication assessment by the pharmacist; 2) an explicit plan to intensify medications if indicated; 3) strategies to improve medication adherence; and 4) follow-up pharmacist visits to sustain BP control. BP was assessed at baseline, 6, 12, 18, 24 and 30 months using a rigorous, standard measurement protocol. The primary outcome measure was the difference in mean BP between the high and low intensity intervention groups. Secondary endpoints included rates of BP control, medication intensification, and medication adherence, as measured by two self-report scales. In addition, a formative evaluation based on semi-structured patient interviews assessed the impact of the pharmacist intervention during the initial 6-month and subsequent follow-up periods.
Study enrollment began in November 2009. Informed consent was obtained from 249 patients who met the study eligibility criteria, including a prior diagnosis of hypertension and uncontrolled BP at the two most recent clinics visits. Of these patients, 122 (49%) had controlled BP (mean BP 126/71), as determined by the study BP measurement protocol, and were not enrolled in the initial 6-month pharmacist intervention. The remaining 127 patients who began the intervention had a mean age of 64.5 10.9 years; 98% were male, 95% were white, and 61% were married.
BP was reduced (P<.01) in diabetic patients by the 6-month intervention. Mean declines were 8.0 14.4 mm Hg for systolic BP and 4.0 9.1 mm Hg for diastolic BP. BP was reduced (P<.001) even more in nondiabetic patients (14.0 11.9 mm Hg and 5.0 10.0 mm Hg for systolic and diastolic BP, respectively). BP was controlled in 69 (54%) patients Of the There were significant differences in medication changes between the controlled and uncontrolled patients, such that the number of medications was increased more frequently in controlled group (P=.04). Thiazide diuretics were used more frequently by patients with controlled than uncontrolled BP (65% vs. 47%; P=.04). Adherence improved from baseline to 6 months, as measured by the Morisky score (P=.002), but did not improve (P=.12) as measured by the Hill-Bone score.
Following the 6-month intervention, 109 patients were randomized to the continued high intensity intervention (n=54) or the low intensity intervention (n=55). Subsequent follow-up data was available for 109 patients at 12 months, 106 at 18 months, 105 at 24 months, and 104 at 30 months.
BP control was similar (P>.1) in high and low intensity intervention patients at all follow-up points: 44% vs. 49% at 12 months, 48% vs. 52% at 18 months, 50% vs. 53% at 24 months, and 61% vs. 53% at 30 months. Mean systolic and diastolic BPs were also similar (P>.1) at each follow-up point. For example mean systolic BPs in the high and low intensity groups were 135 vs. 137 mm Hg and 132 vs. 136 mm Hg at 18 and 30 months, respectively, while mean diastolic BPs were 73 vs. 75 mm Hg and 72 vs. 74 mm Hg, respectively. Medication adherence, as measured by both the Morisky and Hill-Bone scales were also similar in the high and low intensity intervention groups at all follow-up points.
This study provides important insights on the long-term control of BP in patients with HTN. Specifically, the study found that BP control was maintained over a 24 month period by a one-time education intervention following a 6-month high-intensity intervention. Thus, the study findings indicate that patients with uncontrolled HTN who receive a short-term 6-month pharmacist intervention can be provided with a less intense intervention and returned to primary care after the initial intervention.
External Links for this Project
Dimensions for VADimensions for VA is a web-based tool available to VA staff that enables detailed searches of published research and research projects.
If you have VA-Intranet access, click here for more information vaww.hsrd.research.va.gov/dimensions/
VA staff not currently on the VA network can access Dimensions by registering for an account using their VA email address. Search Dimensions for this project
DRA: Health Systems, Cardiovascular Disease
DRE: Treatment - Observational, Prevention, Treatment - Comparative Effectiveness
Keywords: Adherence, Cost effectiveness, Hypertension
MeSH Terms: none