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Cost-effectiveness of Nurse Practitioner/Community Health Worker Care to Reduce Cardiovascular Health Disparities

Allen, Jerilyn K. RN, ScD, FAAN; Dennison Himmelfarb, Cheryl R. RN, ANP, PhD, FAAN; Szanton, Sarah L. PhD, CRNP; Frick, Kevin D. PhD, MA

The Journal of Cardiovascular Nursing: July 2014 - Volume 29 - Issue 4 - p 308–314
doi: 10.1097/JCN.0b013e3182945243
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Background: Although evidence-based guidelines on the management of cardiovascular disease (CVD) and type 2 diabetes have been widely published, implementation of recommended therapies is suboptimal.

Objective: The aim of this study was to evaluate the cost-effectiveness of a comprehensive program of CVD risk reduction delivered by nurse practitioner/community health worker (NP/CHW) teams versus enhanced usual care to improve lipids, blood pressure (BP), and hemoglobin (Hb) A1c levels in patients in urban community health centers.

Methods: A total of 525 patients with documented CVD, type 2 diabetes, hypercholesterolemia, or hypertension and levels of low-density lipoprotein cholesterol, BP, or Hb A1c that exceeded goals established by national guidelines were randomized to NP/CHW (n = 261) or enhanced usual care (n = 264) groups. Cost-effectiveness ratios were calculated, determining costs per percent and unit change in the primary outcomes.

Results: The mean incremental total cost per patient (NP/CHW and physician) was only $627 (confidence interval, 248–1015). The cost-effectiveness of the 1-year intervention was $157 for every 1% drop in systolic BP and $190 for every 1% drop in diastolic BP, $149 per 1% drop in Hb A1c, and $40 per 1% drop in low-density lipoprotein cholesterol.

Conclusions: The findings suggest that management by an NP/CHW team is a cost-effective approach for community health centers to consider in improving the care of patients with existing CVD or at high risk for the development of CVD.

Jerilyn K. Allen, RN, ScD, FAAN M Adelaide Nutting Professor of Nursing, Public Health and Medicine and Associate Dean for Research, School of Nursing, Johns Hopkins University, Baltimore, Maryland.

Cheryl R. Dennison Himmelfarb, RN, ANP, PhD, FAAN Associate Professor, School of Nursing and Medicine, Johns Hopkins University, Baltimore, Maryland.

Sarah L. Szanton, PhD, CRNP Associate Professor, School of Nursing, Johns Hopkins University, Baltimore, Maryland.

Kevin D. Frick, PhD, MA Professor, Bloomberg School of Public Health and School of Nursing, Johns Hopkins University, Baltimore, Maryland.

This study was supported by the National Heart, Lung, and Blood Institute, National Institutes of Health grant R01HL082638.

The authors have no conflicts of interest to disclose.

Correspondence Jerilyn K. Allen, RN, ScD, FAAN, School of Nursing, Johns Hopkins University, 525 N Wolfe St, Baltimore, MD 21205 (jallen1@jhu.edu).

Although evidence-based guidelines on the management of cardiovascular disease (CVD) and type 2 diabetes have been widely published, implementation of recommended therapies is suboptimal.1 The effectiveness of national guidelines for the management of blood pressure (BP), cholesterol, and blood sugar depends upon how well healthcare providers implement the recommended therapies and how well patients adhere to them. Optimizing adherence to healthy lifestyle behaviors and prescribed drugs to manage cardiovascular risk factors is associated with better outcomes and may reduce healthcare costs.2–4

Nurse-led, team-based case management including community health workers (CHWs) has been shown to be an efficacious strategy to improve CVD risk factors in our own and other studies.5–11 Research has also demonstrated that nurse practitioners (NPs) can provide primary care services of equivalent or better quality and at lower cost than similar services provided by other healthcare professionals.12,13

This article summarizes the outcomes and reports on the cost-effectiveness analysis of a program of CVD risk reduction delivered by NP/CHW teams versus enhanced usual care (EUC) to improve lipids, BP, and hemoglobin (Hb) A1c levels in patients in federally qualified metropolitan community health centers.

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Methods

Trial Design

Complete details of the design of the randomized trial, methods, and main findings have been reported previously.8,14 Briefly, the Community Outreach and Cardiovascular Health study was a randomized controlled trial in which 525 patients were randomly assigned to 1 of 2 groups: management of CVD risk factors by an NP/CHW team or an EUC group. Patients in the EUC group received care from their primary provider, which was enhanced by providing feedback on CVD risk factors to both the patients and their providers. Management by the NP/CHW team included tailored educational and behavioral counseling for lifestyle modification, pharmacologic management, and telephone follow-ups between visits.

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Participants

Patients were recruited between July 2006 and July 2009 from 2 community health centers that are part of the Baltimore Medical Systems Incorporated (BMS), a corporation of federally qualified community health centers. The patients were identified from medical records using the International Classification of Diseases, Ninth Revision, codes and were eligible if they had diagnosed CVD, type 2 diabetes, hypercholesterolemia, or hypertension. They had to be African American or white, 21 years or older, and able to speak and understand English. In addition, they had to have at least 1 of the following criteria at the time of the medical record reviews: (1) a low-density lipoprotein cholesterol (LDL-C) of 100 mg/dL or higher or an LDL-C of 130 mg/dL or higher if not diagnosed with CVD or diabetes, (2) a BP of higher than 140/90 mm Hg or higher than 130/80 mm Hg if diagnosed with diabetes or renal insufficiency, or (3) an Hb A1c of 7% or higher or a glucose of 125 mg/dL or higher if with diabetes. Patients were excluded if they had a noncardiac comorbidity with a life expectancy of less than 5 years or if they had a serious psychiatric or neurological impairment that would prevent them from participating in their own care.

Of the 3899 screened for eligibility, 525 were enrolled in the trial (Figure 1). The participants were randomly assigned, stratified by ethnicity and sex, to receive the NP/CHW intervention or EUC. All participants provided written informed consent. The protocol was approved by the Johns Hopkins University institutional review board.

FIGURE 1

FIGURE 1

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Intervention

The NP/CHW intervention focused on evidence-based behavioral interventions to effect therapeutic lifestyle changes and adherence to drugs and appointments as well as the prescription and titration of drugs. The NP and CHW worked as a team and managed the patients for 1 year. The NP functioned as the case coordinator for each patient. She managed the intervention plan, conducted the intervention including counseling for lifestyle modification and drug titration and prescription, supervised the CHW, and conferred with the physician. The patients also met with a CHW who reinforced instructions by the NP related to lifestyle modifications and drug therapies and assisted patients in designing strategies to improve adherence. The intensity of the NP/CHW intervention was based on the achievement of goals and was guided by study algorithms developed from national guidelines.8

The patients in the EUC group and their BMS providers received reports of baseline lipids, BP, and Hb A1c along with the recommended goal levels. The patients also received an American Heart Association pamphlet on controlling CVD risk factors.

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Clinical Outcome Measures

The primary outcomes were changes from baseline evaluation to 1-year follow-up evaluation in lipids, BP, and Hb A1c. Total cholesterol, triglycerides, and high-density lipoprotein cholesterol were measured directly after a 12-hour fast. Low-density lipoprotein cholesterol was estimated using the Friedewald equation.15 If triglyceride levels were greater than 400 mg/dL, LDL-C was measured directly through ultracentrifugation methods. Hemoglobin A1c was measured using high-pressure liquid chromatography. Blood pressure was measured using the Omron Digital Blood Pressure Monitor HEM-907XL automatic BP device according to Joint National Committee 7 guidelines.16 The mean of 3 BPs was noted.

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Resource Use Measurement and Cost Assignment

The cost-effectiveness evaluation was performed from a health services perspective. It was assumed that if a healthcare organization were to add these NP/CHW case management services, no additional office space and equipment would be necessary. Costs were not discounted because the period of the intervention was 1 year. Costs that were related to the process of the research rather than to the delivery of the intervention were not included.

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Provider Costs

Nurse practitioner and CHW time spent delivering the intervention was collected for a sample of 30% of the patients for 1 year. The patients in this sample were selected consecutively, beginning with a randomly selected patient. The NP and the CHW recorded details of patient encounters, including the length of encounters to the closest minute and the types of activities carried out as part of the interventions such as medication counseling, lifestyle counseling, feedback on laboratory results, and physical examinations. They also captured time for preparation and follow-up activities related to the intervention but outside the direct encounter with the patient. This nonencounter time included activities such as preparation for visits, documentation in the medical record, consultation with other healthcare providers, and contacting the pharmacy or insurance agency. The number of visits during the year of intervention was also captured.

The NP and CHW salaries were based on the standard wage rates in the 2010 Occupational Employment and Wages from the Bureau of Labor Statistics national estimates for the respective occupations.17 The median hourly wage for NPs (health diagnosing and treating practitioners) was $33.32; and for CHWs (community and social services specialists), $18.32. Adjustments of an additional 30% for benefits resulted in a final hourly rate of $51.14 for the NP and $25.78 for the CHW.

To determine the costs of providing healthcare for the management of the same conditions in the usual care group, a chart review was completed on a random sample of 53 patients randomized to receive usual care. Data were collected on the number of visits to a BMS healthcare provider for the treatment of their CVD, hypertension, hypercholesterolemia, or diabetes during the year of enrollment in the clinical trial. Expert opinion from the primary care practitioners estimated 1 hour to conduct the patient encounter and necessary follow-up documentation of these moderate- to high-intensity–level visits. According to the national estimates,17 the mean hourly wage for family and general physicians was $83.59. Adding 30% for benefits, the hourly wage for other healthcare provider visits was $108.67.

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Laboratory Test Costs

The costs for laboratory tests used to monitor response and side effects of therapy during the year that patients were in the study were included in the calculations. A chart review of a random sample of 53 patients in the usual care group and 53 patients in the intervention group provided a mean number of lipid panels, liver function tests, and Hb A1c tests per patient. The laboratory costs for the tests used in the analyses were $36 for a lipid panel, $42 for liver function tests, and $35 for Hb A1c.

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Drug Costs

An annual mean estimate of drug costs per patient was calculated for each group. Current cardiovascular, lipid-lowering, antihypertensive, and diabetes drugs were identified by patient interview at 6 and 12 months. It was assumed that the patient was on the same drugs for the previous 6-month period. The categories included in these assessments were antihypertensive drugs, lipid-lowering drugs, drugs to treat coronary artery disease, oral hypoglycemics, and insulin. The cost of a 1-month supply of each drug was determined from the 2010 Drug Topics Red Book average wholesale price.18 This cost was multiplied by 6 (6 months of drugs) and added to the other 6-month cost to determine the annual cost for each drug. A total annual cost of all cardiac, hypertensive, lipid-lowering, and diabetes drugs was calculated for each patient.

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Statistical Methods

Primary outcome measures were analyzed with an intention-to-treat analysis. General linear mixed models were used to model each outcome variable as a function of time and intervention group, controlling for age, sex, race, education, body mass index, insurance, and an indicator of in-control for clinical outcome at baseline.

A clinician time cost for each patient was calculated by multiplying the mean cost per hour of the practitioners’ time (NP and CHW for the intervention group and other BMS primary care provider in the usual care group) by the mean time per visit by the mean number of visits. This provider cost was added to the mean total cost of drugs and laboratory testing to determine the mean total costs per patient. Cost-effectiveness was calculated using 4 cost-effectiveness ratios, with the cost associated with the usual care group subtracted from the cost associated with the intervention group as the numerator, and the clinical benefit (percentage of reduction in LDL-C, systolic and diastolic BP, and Hb A1c) in the usual care group subtracted from the clinical benefit in the intervention group as the denominator.

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Results

Sample Characteristics

The sample was predominantly black (79%) and female (71%). A majority of the patients had annual incomes of less than $20,000 despite having at least a high school education. Less than half had private health insurance. The groups were similar in sociodemographic and baseline measures except for higher Hb A1c levels in the NP/CHW intervention group compared with the EUC group (Table 1). There was no statistically significant differential attrition between the 2 groups. Ninety-four percent (n = 467) completed the 1-year assessment, with no differences between completers and noncompleters in baseline lipids, Hb A1c, BP, age, education, race, or sex.

TABLE 1

TABLE 1

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Treatment

During the course of the 1 year of intervention, the patients had a mean of 7.6 (confidence interval [CI], 6.9–8.2) encounters with the NP and 5.3 (CI, 4.8–5.9) encounters with the CHW (Table 3). This is relative to the mean of 2.8 (CI, 2.2–3.5) visits to other healthcare providers for cardiac or diabetes management in the usual care group. A total of 84% of the patients randomized to the intervention group completed an initial visit, and 70% had at least 4 in-person visits with the nurse. Figure 2 details the percentage of time the NP and the CHW spent in the various activities that composed the intervention. The NP had a mean of 17 (CI, 16–19) minutes per direct encounter time with the patient and another 16 (CI, 14–17) minutes for nonencounter activities. The highest percentage of time with the patient was spent in counseling regarding medications (43%), followed by lifestyle counseling (22%), physical examination (22%), and providing feedback about laboratory results (13%). A large majority (76%) of the nonencounter time was spent in documentation, followed by preparation of activities (17%) and coordination of care (7%). The CHW spent a mean of 11 minutes per encounter, which included in-person and telephone follow-ups, with a majority of her time focusing on lifestyle counseling (66%), followed by reinforcement of medication counseling (28%) and evaluation of barriers to control (6%). Documentation was the major focus of the CHW’s time outside direct patient contact (70%).

FIGURE 2

FIGURE 2

At 12 months, the patients in the intervention group had significantly greater overall improvement in LDL-C, systolic and diastolic BP, and Hb A1c compared with the patients receiving EUC (Table 2). The estimated between-group differences were statistically and clinically significant. At the 12-month follow-up, a significantly higher percentage of the patients in the intervention group compared with the EUC group had values that reached guideline goals or showed clinically significant improvements in LDL-C (EUC, 58%; NP/CHW, 75%; P < 0.001), systolic BP (EUC, 74%; NP/CHW, 82%; P = 0.018), and Hb A1c (EUC, 47%; NP/CHW, 60%; P = 0.016).

TABLE 2

TABLE 2

TABLE 3

TABLE 3

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Cost-effectiveness

The resources used per patient by arm are presented in Table 3. The increase in laboratory testing and medications in the more intensive intervention arm is apparent, contributing to the increased overall cost of the intervention compared with the cost for usual care. Although the patients in the intervention arm were, on average, taking fewer than 1 additional medication compared with those in the usual care arm, the drugs of the patients in the intervention arm were more likely to be titrated to a higher dosage, which likely contributed to not only better efficacy but also significantly more expense. In addition, closer monitoring according to guideline recommendations lead to more laboratory tests in the intervention group. The total cost for 1 year of intervention from the NP/CHW team exceeded the cost for physician care; however, the mean incremental total cost per patient (NP/CHW and physician) was only $627 (CI, 248–1015).

The cost-effectiveness ratios are presented in Table 4. The cost-effectiveness of the 1-year intervention was $157 for every 1% drop in systolic BP and $190 for every 1% drop in diastolic BP, $149 per 1% drop in Hb A1c, and $40 per 1% drop in LDL-C. The costs for every unit drop in outcome were similar except for Hb A1c, with a cost of $1255 for a drop of 1 unit (ie, from 8% to 7%).

TABLE 4

TABLE 4

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Discussion

Comprehensive management of cardiovascular risk factors by the NP/CHW teams that includes lifestyle counseling, drug prescription and titration, and promotion of compliance is a cost-effective strategy to reduce cardiovascular risk and thereby address health disparities in underserved, minority populations. Chronic illness care in medically underserved patients with CVD or at high risk for CVD is complex. These data add to the body of evidence that specially trained nurse-led teams are efficacious strategies to improve management. A sizeable body of research reinforces that patient care outcomes are similar and sometimes better when patients are managed by NPs as primary care providers as compared with physicians.19 As the costs of healthcare for chronic diseases continue to increase, NPs are in pivotal positions to address the need for safe, effective, patient-centered, efficient, and equitable healthcare.20

This study also provides evidence that a nurse-led team that includes CHWs is an effective model of care. Community health workers are critical members of these teams. They share perspectives and experiences that enhance trust, enabling them to effectively bridge communication gaps between patients and healthcare providers and intervene to decrease barriers to adherence. However, adoption and sustainability of this model of care will require financing mechanisms for CHWs. Funding, reimbursement, and payment policies for CHWs must be established to ensure that CHW models are adopted in mainstream healthcare.21,22

Although it is atypical to have 4 separate cost-effectiveness ratios in a single study, the relatively low incremental cost-effectiveness ratios for each outcome suggest that the effect of any 1 of the clinical changes may be sufficient to offset the costs. With all 4 changes simultaneously, this would only amplify the individual economic outcomes. The relatively small incremental cost for the additional benefit of LDL-C, BP, and Hb A1c lowering seen in the NP/CHW group could yield meaningful downstream differences in morbidity and mortality from coronary heart disease (CHD). Clinical trials23 with statin lipid-lowering drugs in patients indicate that a 1% decrease in LDL-C reduces the risk for CHD by approximately 1%. The benefit is even greater in those with existing CHD or diabetes, a CHD equivalent, decreasing stroke rates, improving angina and myocardial perfusion, and decreasing the need for subsequent revascularization.23 Stamler24 estimated that a 5–mm Hg reduction of systolic BP in the adult population would result in a 14% overall reduction in mortality due to stroke.

In conclusion, this study supports NP/CHW teams using evidence-based treatment algorithms as a cost-effective, successful strategy to implement national guidelines for the management of hyperlipidemia, hypertension, and diabetes in high-risk vulnerable populations. This is particularly relevant as we plan for the release of the new national guidelines in 2013.

During the next 5 years, the Affordable Care Act legislation will be infusing 11 billion dollars into community health centers such as the BMS.25 Nurse practitioners and CHWs are underused resources who should be incorporated into this healthcare reform to increase the quality of care and improve patient outcomes for patients with chronic conditions. The results of this trial also support the potential for nurse-led patient-centered medical homes to improve the quality of care in high-risk underserved populations.

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What’s New and Important?

  • Comprehensive management of cardiovascular risk factors by NP/CHW teams that includes lifestyle counseling, drug prescription and titration, and promotion of adherence is a cost-effective strategy to reduce cardiovascular risk.
  • Nurse practitioners and community health workers are underused resources who should be incorporated into the healthcare reform to increase the quality of patient-centered care and address health disparities in underserved, minority populations.
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Acknowledgments

The authors thank the patients who participated in the program and the administration and the staff of Baltimore Medical Systems for their collaboration in the design and implementation of the program. The authors also thank Carol Curtis for her coordination of the research and assistance in the preparation of this article.

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Keywords:

cardiovascular risk factors; community health worker; cost-effectiveness; nurse practitioner; prevention

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