Abstract
The purposes of this study are to investigate the cost‐effectiveness of an implantable carotid body stimulator (Rheos; CVRx, Inc, Minneapolis, MN) for treating resistant hypertension and determine the range of starting systolic blood pressure (SBP) values where the device remains cost‐effective. A Markov model compared a 20‐mm Hg drop in SBP from an initial level of 180 mm Hg with Rheos to failed medical management in a hypothetical 50‐year‐old cohort. Direct costs (2007$), utilities, and event rates for future myocardial infarction, stroke, heart failure, and end‐stage renal disease were modeled. Sensitivity analyses tested the assumptions in the model. The incremental cost‐effectiveness ratio (ICER) for Rheos was $64,400 per quality‐adjusted life‐years (QALYs) using Framingham‐derived event probabilities. The ICER was <$100,000 per QALYs for SBPs ≥142 mm Hg. A probability of device removal of <1% per year or SBP reductions of ≥24 mm Hg were variables that decreased the ICER below $50,000 per QALY. For cohort characteristics similar to Anglo‐Scandinavian Cardiac Outcomes Trial–Blood Pressure–Lowering Arm (ASCOT‐BPLA) participants, the ICER became $26,700 per QALY. Two‐way sensitivity analyses demonstrated that lowering SBP 12 mm Hg from 220 mm Hg or 21 mm Hg from 140 mm Hg were required. Rheos may be cost‐effective, with an ICER between $50,000 and $100,000 per QALYs. Cohort characteristics and efficacy are key to the cost‐effectiveness of new therapies for resistant hypertension .
Elevated systolic blood pressure (SBP) is an important risk factor for cardiovascular (CV) and cerebrovascular disease, and CV risk doubles for each 20‐mm Hg increment above 115 mm Hg. 1 Hypertension can be effectively treated, in most cases, through lifestyle changes and medications. However, even with the best medical care, some individuals develop resistant hypertension. The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7) defines resistant hypertension as failing to achieve blood pressure (BP) targets while adhering to a 3‐medication regimen, one of which is a diuretic. 1
Additional treatment options for individuals with resistant hypertension include an implantable device and a novel agent. Rheos (CVRx, Inc, Minneapolis, MN) is a device surgically implanted near the clavicle with leads that stimulate the carotid baroreflex system, thereby reducing BP. Rheos lowered SBP by 21 to 35 mm Hg in several phase I trials. 2 , 3 , 4 Aliskiren is the first medication available in a new class of antihypertensive agents, the direct renin inhibitors. A 300‐mg daily dose lowered SBP by 5 to 11 mm Hg. 5
Despite the apparent efficacy of Rheos and aliskiren, neither have been subjected to a formal cost‐effectiveness analysis. Most cost‐effectiveness analyses of treating hypertension are based on adding or comparing conventional medications. 6 , 7 The costs of the Rheos device, surgical implantation, and maintenance differ from the continual monthly costs of medications. The initial cost of Rheos must be offset by the prevention of hypertension‐related morbidity and mortality. Thus, the purposes of this analysis are 2‐fold. First, is to determine the cost‐effectiveness of Rheos as new adjuvant therapy that results in 20‐mm Hg SBP reduction from a starting SBP of 180 mm Hg compared with failed medical management. The second goal is to determine the range of SBP levels over which the device is cost‐effective. The cost‐effectiveness of aliskiren is presented as a point of comparison and as an additional evaluation of the cost‐effectiveness model.
Methods
Model Description
A Markov model incorporated future adverse events (AEs), costs, and benefits of treatment with Rheos compared with failed best medical therapy (TreeAge, Williamstown, MA). The cycle length was 1 year. A hypothetical cohort of 1000 patients began in the healthy state. The control cohort could remain healthy or transition to death, stroke, heart failure (HF), end‐stage renal disease (ESRD), or myocardial infarction (MI) (Figure S1 and Figure S2). The analysis ended when the hypothetical cohort reached the absorbing death state.
The 2‐year Rheos data suggest that there is no rebound in SBP. 3 Thus, the SBP decrease was maintained throughout the life of the cohort. For those in the Rheos branch, there was also the possibility of device removal from the healthy state. If the device was removed, the BP was returned to the initial systolic level. The probabilities of AEs were then adjusted to reflect the risks associated with resistant hypertension.
Cardiac events included fatal coronary heart disease or MI. Once an MI occurred, the individual was transitioned to an MI branch where the probabilities of AEs incorporated a history of CV disease. The MI branch allowed transitions to death, stroke, HF, ESRD, or fatal coronary heart disease. Recurrent MI was possible and the transition was back to the MI branch.
Stroke was divided into transient ischemic attack (TIA), major ischemic stroke, and hemorrhagic stroke (including both subarachnoid and intracerebral hemorrhage). TIA was a temporary state where function recovered completely. Therefore, after a TIA, the transition was back to the original state. Major ischemic stroke, major hemorrhagic stroke, HF, and ESRD were considered serious health states from which individuals could not recover. The transitions from major ischemic stroke, major hemorrhagic stroke, HF, and ESRD were to continue in the current state or death.
Target Population
The target population was an asymptomatic 50‐year‐old cohort with uncontrolled hypertension, despite polypharmacologic management, and no history of CV disease or stroke. The cohort age of 50 reflected phase I Rheos trials. 2 , 4 Initial SBPs varied from 140 to 220 mm Hg.
Perspective and Time Horizon
The payer perspective was modeled and included direct medical costs relating to device therapy and adverse health events. The time horizon was the lifetime of the cohort.
Probability Data
Probabilities for HF, stroke, MI, and fatal coronary heart disease were based on Framingham studies (Table I, Table SIA). 8 , 9 , 10 The probability of ESRD and proportions for the stroke subtypes and severity were obtained from the literature. 11 , 12 , 13 The prevalence of diabetes mellitus (DM), ESRD‐related mortality, and atrial fibrillation increased with age (Table SIB–D). Please see the online supplement for information on prevalence of risk factors for the Framingham equations and relative risks given medical history.
Table I.
Key Model Parameters
| Variable | Base Case | Range | References |
|---|---|---|---|
| Age, y | 50 | 40–70 | Estimate |
| Initial SBP, mm Hg | 180 | 140–220 | Estimate |
| Change with treatment, mm Hg | 20 | 5–40 | Estimate |
| ESRD baselinea | 0.000045 | 0.000036–0.000058 | 11 |
| Cerebral ischemia (all) | Framingham | ||
| TIA (% of all events) | 0.264 | 12 | |
| IS | 0.64 | 0.5–0.75 | 12, 13 |
| ICH+SAH | 0.096 | 0–0.15 | 13 |
| IS, % fatal | 0.073 | 0.047–0.111 | 55 |
| SAH+ICH, % fatal | <65: 0.33 ≥65: 0.45 | 55, 56 | |
| Excess mortality after ICH or SAH | 0.051 | 0–0.15 | 57 |
| Device removal | 0.02 | 0–0.06 | Estimate |
| Base Caseb | Rheos Rate | Untreated Rate | |
|---|---|---|---|
| ESRD, 5 | 0.0172 | 0.0175 | 11 |
| Heart failure, % | 0.21 | 0.24 | 8 |
| MI + fatal CHD, % | 0.19 | 0.32 | 9 |
| All stroke, including TIA, % | 0.37 | 0.46 | 10 |
Abbreviations: CHD, coronary heart disease; ESRD, end‐stage renal disease; ICH, intracerebral hemorrhage; IS, ischemic stroke; MI, myocardial infarction; SAH, subarachnoid hemorrhage; SBP, systolic blood pressure; TIA, transient ischemic attack. Additional model parameters are in the supplement. aFurther modified by a relative risk of ESRD given SBP (Table SIB). bBase case rates (% per year) for adverse events in the first Markov cycle. Framingham‐derived rates were used for heart failure, MI+fatal CHD, and cerebrovascular events. Subsequent Markov cycles vary based on age and comorbidities.
To test resistant hypertension treatment in a different cohort, probabilities from the Anglo‐Scandinavian Cardiac Outcomes Trial–Blood Pressure–Lowering Arm (ASCOT‐BPLA) were modeled separately from the Framingham equations. 14 , 15 The initial age for models of the ASCOT‐BPLA cohort was 63 years, the average age of participants in this trial.
Cost and Utilization Data
Costs for the device, the surgical implantation or removal procedure, and ongoing maintenance were estimated (Table II). Costs of hospitalization following AEs and of continuing care were obtained from the 2005 Nationwide Inpatient Sample of the Health Care Utilization Project and from the literature. 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 The hospitalization cost of a hemorrhagic stroke assumed that 23% of these events were subarachnoid hemorrhage and the remaining were intracerebral hemorrhage. All costs were adjusted to 2007 US dollars using the Consumer Price Index for medical care. As this comparison focused on the differences between a new device and continued medical management, follow‐up and medication costs shared by both branches were not included. Once Rheos failed as a treatment, the costs of maintenance no longer accrued.
Table II.
Costs (2007 US$) and Utilities
| Costs, Per Year | Base Case | Range | References |
|---|---|---|---|
| Maintenance | 200 | 0–1000 | Estimate |
| ESRD | 75,500 | 37,750–155,000 | 16, 17 |
| MI | 3800 | 1,000–10,000 | 18, 19, 20, 21, 22 |
| HF (1st year) | 27,500 | 13,750–55,000 | 23 |
| HF (2+ years) | 6000 | 3,400–15,000 | 22, 23, 24, 25 |
| Stroke (1st year) | 56,400 | 28,200–112,800 | 20, 26, 27, 28 |
| Stroke (remaining years) | 31,700 | 16,850–63,400 | 20, 26, 27, 28 |
| One‐time event costs | |||
| MI | 20,300 | 15,000–60,000 | 18, 19, 20, 22 |
| ICH | 10,800 | 7,000–17,800 | 32 |
| IS | 11,500 | 6,000–16,000 | 21, 26, 29, 30, 31 |
| SAH | 10,600 | 9600–30600 | 29 |
| TIA | 9400 | 6,000–16,000 | 21, 26, 29, 30 |
| Device | 10,000 | 5,000–20,000 | Estimate |
| Procedure | 10,000 | 5,000–20,000 | Estimate |
| Utilities | |||
| Hypertension | 0.98 | 0.9–1.0 | 33 |
| ESRD | 0.7 | 0.5–0.9 | 34, 35 |
| HF | 0.69 | 0.3–0.9 | 36, 37, 38, 39 |
| ICH | 0.55 | 0.3–0.8 | 40, 41 |
| IS | 0.3 | 0–0.5 | 42, 43, 44, 45 |
| MI | 0.88 | 0.5–1.0 | 46, 47 |
| TIA | 0.89 | 0.5–1.0 | 43, 48 |
| Discount rate | 0.03 | 0–0.08 | 49 |
Abbreviations: ESRD, end‐stage renal disease; HF, heart failure; ICH, intracerebral hemorrhage; IS, ischemic stroke; MI, myocardial infarction; SAH, subarachnoid hemorrhage; TIA, transient ischemic attack.
Utility Data
Utilities, or health state preferences, were obtained from the literature (Table II). 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 The occurrence of a TIA reduced the utility proportionally. For example, a TIA with a history of MI had a utility of 0.7832 for the year (0.88 utility of an MI*0.89 utility of a TIA). Utilities adjustments for side effects and surgical implantation or removal were not included. Quality‐adjusted life‐years (QALYs) represent utility multiplied by the duration of the health state. For example, if someone has a post‐MI utility for 1.5 years, it contributes 1.32 QALYs (utility of 0.88 for an MI*1.5 years).
Analysis
All future costs and utilities were discounted at 3%. 49 The Rheos branch, the newest and more expensive option, was the intervention. Best medical management, although failing to reach recommended BP guidelines, was the comparator. The intervention was considered cost‐effective if the incremental cost‐effectiveness ratio (ICER) was below $50,000 per QALY. If the intervention exceeds $100,000 per QALY, the intervention was considered cost‐ineffective. ICERs between $50,000 and $100,000 per QALY were in a grey area.
Results
Base Case Analysis
Lowering SBP by 20 mm Hg with Rheos in a 50‐year‐old cohort with resistant hypertension yielded 16.868 QALYs at a cost of $72,699. In comparison, best medical management where SBP remained at 180 mm Hg produced 16.584 QALYs at a cost of $54,421 over a lifetime. The incremental cost of Rheos was $18,278 and the incremental QALY gain was 0.284. Thus, the ICER for lowering SBP with Rheos was $64,400 per QALY gained.
When to Treat Resistant Hypertension
The ICER for Rheos remained below $100,000 per QALY as long as the initial SBP was ≥142 mm Hg (Figure 1A). The ICER decreased below $50,000 per QALY if the initial SBP was ≥206 mm Hg.
Figure 1.
(A) Tornado diagram of the 1‐way sensitivity analyses of the prevalence and probability assumptions. Rheos was cost‐effective in patients with diabetes mellitus (DM), with high total cholesterol/high‐density lipoprotein (TC/HDL) ratios, with a low probability of device removal, and with larger changes in systolic blood pressure (SBP) and at higher initial SBPs. (B) Tornado diagram of the 1‐way sensitivity analyses of the costs, discount rate, and utilities. The ongoing costs of device maintenance (per year) could increase the incremental cost‐effectiveness ratio (ICER) beyond $100,000 per quality‐adjusted life‐years (QALYs). Lower device and procedure costs (≤$5,900) would make Rheos cost‐effective. The assumptions about the discount rate and the utility of a myocardial infarction (MI) (≤0.54) also influence the model.
One‐Way Sensitivity Analyses
A series of 1‐way sensitivity analyses tested the individual assumptions in the model (Figure 1A). Rheos became clearly cost‐effective (ICER<$50,000 per QALY) if the SBP decrease was ≥24 mm Hg from an initial level of 180 mm Hg. Further reductions in SBP of 30 mm Hg 4 and 35 mm Hg 3 led to ICERs of $34,380 per QALY and $26,959 per QALY, respectively. Rheos was cost‐ineffective (ICER >$100,000 per QALY) when the change in SBP was <14 mm Hg. Rheos was cost‐effective in patients with DM or a poor lipid profile (total cholesterol/high‐density lipoprotein ratio). As the probability of device removal dropped below 1%, the ICER for Rheos was cost‐effective.
Costs and utilities were also tested individually (Figure 1B). If the cost of maintenance exceeded $900 per year, the ICER for Rheos was >$100,000 per QALY. As the cost of the device or the procedure dropped below $6000, the ICER for Rheos decreased below $50,000 per QALY. Utilities of <0.55 for MI were associated with an ICER <$50,000 per QALY. A low utility for an MI caused an incremental QALY gain for Rheos (and, in turn, a lower ICER) because quality of life was preserved when MIs were avoided. The discount rate also influenced the ICER.
There was a biphasic relationship between age at the initiation of therapy and the ICER for Rheos. The ICER decreased as the initial age increased from 40 to 60 years (Figure 2A), then increased again for ages 60 to 70 years. However, the ICER did not exceed $100,000 per QALY. The U shape was attributed to the underlying changes in the incremental QALYs (Figure 2B). Incremental costs decreased from $20,022 to $17,058 as the starting age increased from 40 to 70 years. However, incremental QALYs increased from 0.24 at age 40 through 0.30 at age 57. Beginning at the age of 58, incremental QALYs decreased to 0.26 at age 70. The incremental QALYs decrease (the denominator of the ICER) occurred at a greater rate than the decrease in incremental costs, thus causing the ICER increase at age 60.
Figure 2.
(A) The incremental cost‐effectiveness ratio (ICER) for Rheos decreases until the age of 60. (B) The incremental costs of Rheos therapy (left y axis) decrease as age increases. Incremental quality‐adjusted life‐years (QALYs) increase (right y axis) until the age of 60, at which point they decrease with age. The net effect is the U shaped ICER curve in panel A.
Sex also had a role in the cost‐effectiveness of resistant hypertension treatment. The ICERs of Rheos for women and men, using sex‐specific mortalities, were $57,200 per QALY and $71,000 per QALY, respectively (Table III).
Table III.
Base Case Analysis for 50‐Year‐Old Patients With a Starting SBP of 180 mm Hg and a 20‐mm Hg Drop With Rheos
| Cost (2007 US$) | Incremental Cost | QALY | Incremental QALY | ICER ($ per QALY) | |
|---|---|---|---|---|---|
| Base case | |||||
| Resistant HTN | 54,421 | 16.584 | |||
| Rheos | 72,699 | 18,278 | 16.868 | 0.284 | 64,400 |
| Women | |||||
| Resistant HTN | 60,610 | 17.15 | |||
| Rheos | 77,769 | 28,552 | 17.45 | 0.3 | 57,200 |
| Men | |||||
| Resistant HTN | 48,668 | 15.98 | |||
| Rheos | 67,351 | 18,683 | 16.243 | 0.263 | 71,000 |
| Alternatives | |||||
| Aliskiren vs resistant HTN | 67,470 | 13,049 | 16.729 | 0.145 | 90,000 |
| Rheos vs aliskiren | 5229 | 0.139 | 37,600 | ||
Abbreviations: ICER, incremental cost‐effectiveness ratio; QALY, quality‐adjusted life‐years. Rheos was more cost‐effective in women than men. Alternative comparisons showed the cost‐effectiveness of treating resistant hypertension (HTN) with aliskiren and compared Rheos with aliskiren.
Sensitivity Analysis: Another Medication for Resistant Hypertension
The cost‐effectiveness of adding aliskiren to reduce SBP instead of an implantable device was tested. An 11.2‐point SBP reduction for aliskiren was assumed for a 300‐mg dose, at a cost of $1220 per year. 5 The discontinuation rate was 2.2% per year. 5 The lifetime cost for aliskiren became $67,470 for 16.729 QALYs gained (Table III). The QALYs and costs for untreated resistant hypertension remained the same. Thus, the ICER for aliskiren compared with failed medical management was $90,000 per QALY. The ICER for Rheos compared with aliskiren was $37,600 because Rheos had a greater QALY gain with higher costs.
Sensitivity Analysis: Characteristics of the ASCOT‐BPLA Cohort 14 , 15
To test the cost‐effectiveness of treating resistant hypertension in a hypothetical cohort whose risks were different than those in Framingham, AE rates from the ASCOT‐BPLA trial were incorporated into the model. The starting age was adjusted to 63 years to match the age of the ASCOT‐BPLA cohort. The ICER for Rheos therapy in an ASCOT‐BPLA–like cohort was $26,700 per QALY (Table IV). Compared with a hypothetical 63‐year‐old cohort using Framingham probabilities, the ASCOT‐BPLA best medical management arm, with SBP remaining at 180 mm Hg, had reduced costs and increased QALYs. This reduced the ICER, compared with the Framingham‐based model, reflecting both decreased incremental costs and increased incremental QALYs. With CV and cerebrovascular risks similar to the ASCOT‐BPLA cohort, treating hypertension remained cost‐effective (ICER <$50,000 per QALY) down to an SBP of 158 mm Hg. Even with an initial SBP of 140 mm Hg, the ICER for Rheos in the ASCOT‐BPLA cohort remained below $100,000 per QALY.
Table IV.
Sensitivity Analysis for 63‐Year‐Old Patients With a Starting SBP of 180 mm Hg and a 20‐mm Hg Drop With Rheos Comparing Adverse Events Based on Framingham Equations or ASCOT‐BPLA Rates
| Cost (2007 US$) | Incremental Cost | QALY | Incremental QALY | ICER ($ per QALY) | |
|---|---|---|---|---|---|
| Framingham | |||||
| Best medical management | 49,458 | 11.844 | |||
| Rheos | 66,582 | 17,124 | 12.134 | 0.29 | 59,000 |
| ASCOT‐BPLA | |||||
| Best medical management | 47,592 | 11.995 | |||
| Rheos | 60,266 | 12,674 | 12.469 | 0.474 | 26,700 |
Abbreviations: ASCOT‐BPLA Anglo‐Scandinavian Cardiac Outcomes Trial–Blood Pressure–Lowering Arm; ICER, incremental cost‐effectiveness ratio; QALY, quality‐adjusted life‐years; SBP, systolic blood pressure.
Two‐Way Sensitivity Analysis
A 2‐way sensitivity analysis was performed to study the relationship between initial SBP and change in SBP. With a willingness‐to‐pay of $100,000 per QALY, Rheos must lower SBP by 12 points from an initial level of 220 mm Hg to remain cost‐effective (Figure 3, where the initial age equals 50). Likewise, SBP must be lowered by at least 21 points if the initial SBP is 140 mm Hg. For cohort ages older than 50, Rheos, with a 20‐ to 21‐mm Hg SBP decrease, was preferred over best medical management with resistant hypertension at all initial SBP levels tested (range, 140–220 mm Hg). For a 40‐year‐old cohort with initial SBPs <160 mm Hg, best medical management with resistant hypertension is the favored treatment, unless the SBP decrease with Rheos exceeds 20 mm Hg.
Figure 3.
Two‐way sensitivity analysis. With a willingness‐to‐pay of $100,000 per quality‐adjusted life‐years, varying the change in blood pressure and the initial blood pressure leads to different choices for therapy. Continuing with best medical therapy without Rheos is favored with lower initial and changes in blood pressure (below the line). SBP indicates systolic blood pressure.
Discussion
This study reports the cost‐effectiveness of treating resistant hypertension in a 50‐year‐old cohort using a novel surgically implanted device and reports at which SBP to begin treatment. The ICER for Rheos falls in a grey area between too expensive (>$100,000 per QALY) and an acceptable price (<$50,000 per QALY). Rheos performs as well as, if not better, than the base case assumptions. The base case incorporated a 20‐mm Hg SBP decrease because most achieved this decrease at 2 years (average, 35±8 from initial SBPs of 191±32 mm Hg). 3 Current Rheos performance suggests that the device may lower SBP by an average of 30 mm Hg 4 to 35 3 mm Hg. These alternatives were included in the sensitivity analyses and were cost‐effective. Rheos would also be an adoptable technology at higher initial SBPs or when individuals have a risk profile similar to the ASCOT‐BPLA cohort.
The costs of the actual device or the surgery have not been definitively established. The estimated hospital cost for implantation of a carotid baroreflex activation device is $8400 (International Classification of Diseases, Ninth Revision procedure code 39.8). 50 Our base case cost for the procedure and the device is $20,000, approximately the 2007 hospital cost for a deep brain stimulator ($18,800). 50 The 1‐way sensitivity analysis showed that doubling the cost of the procedure generates an ICER of $99,500 (Figure 1B). Here, the costs total $30,000 for the device ($10,000) and the procedure ($20,000).
The ICER for aliskiren was explored as a comparable treatment for resistant hypertension. The ICER of $90,000 per QALY also falls within a grey area as an acceptable price for a new medication. Lastly, comparing Rheos to aliskiren still showed that the surgically implanted device should still be adopted as a cost‐effective treatment.
The cost‐effectiveness of Rheos was comparable to other implantable devices analyzed within the setting of US health care. The base case ICER of $64,400 for Rheos was close to the ICER for deep brain stimulation for Parkinson’s disease treatment and within the range of values for implantable cardiac defibrillators (Table V). 51 , 52 A United Kingdom–based study showed that left ventricular assist devices as destination therapy had considerably higher costs per QALY gained. 53 Lastly, a Canadian study demonstrated the cost‐effectiveness of losartan as an alternative to an atenolol‐based regimen using data from the Losartan Intervention for Endpoint Reduction in Hypertension (LIFE) study. 54 Adding or switching certain medications for hypertension treatment remains the first treatment option. For resistant hypertension, Rheos had a favorable cost‐effectiveness profile to other surgically implanted devices.
Table V.
Incremental Cost‐Effectiveness Ratios for Hypertension Treatment and Other Surgically Implanted Devices (2007 US$)
| Treatment | Base Case or Range ($ per QALY) | References |
|---|---|---|
| HTN (LIFE) | 1350 | 54 |
| ICD | 37,000–76,000 | 51 |
| LVAD, destination therapy | 329,600 | 53 |
| DBS | 66,000 | 52 |
Abbreviations: DBS, deep brain stimulation for Parkinson’s disease; HTN, hypertension; ICD, implantable cardiac defibrillator; LIFE, Losartan Intervention for Endpoint Reduction in Hypertension trial; LVAD, left ventricular assist device.
This analysis of resistant hypertension is consistent with other cost‐effectiveness analyses of new medications to manage traditional hypertension. 6 , 7 Treating resistant hypertension becomes more cost‐effective in persons with a higher CV risk including those with diabetes. Contrary to other literature, the cost‐effectiveness of Rheos does not improve beyond 60 years or improve with male sex. Rheos therapy was more cost‐effective in hypertensive women than men. The prediction equations have a higher relative risk of stroke or MI associated with female sex, thus supporting the observation that treating hypertension in women is more cost‐effective than treating hypertension in men. 9 , 10
Limitations
The use of prediction equations for AEs rather than event rates based on a clinical trial is a limitation to this study. Framingham‐based prediction equations allow a broad look at many end points but may lack the accuracy of the device’s performance in its specific patient population. This limitation has been addressed, in part, by also modeling probabilities from ASCOT‐BPLA trial. Another limitation is the use of direct costs and utilities from the literature rather than incorporating indirect patient costs. The strengths of this study are the inclusion of HF and dialysis‐dependent renal disease with the common disease states of MI and stroke.
Conclusion
One important question is whether the SBP reductions achieved in the Rheos phase I trials are maintained throughout the Rheos Pivotal Trial (clinicaltrials.gov id: NCT00442286). With a finite pool of health care dollars, new effective technology or medications must have reasonable cost to justify widespread use. The cost‐effectiveness of Rheos is dependent on the starting SBP, performance of the device, and the risks of the target population. Decreases of 30 mm Hg 3 , 4 or more support the use of Rheos as a cost‐effective treatment for resistant hypertension regardless of the initial SBP.
Disclosures: KCY and JCT have been supported in part by National Institutes of Health (NIH) T32HL007937 (to Thomas A. Pearson, MD, PhD, MPH, Department of Community and Preventive Medicine, University of Rochester). CGB is supported in part by NIH RO1HL080107. Some of our data were derived from US Renal Data System (USRDS) estimates, therefore, the data reported here have been supplied by the USRDS. The interpretation and reporting of these data are the responsibility of the author(s) and in no way should be seen as an official policy or interpretation of the US government. KCY: Portion of stipend through an NIH training grant (see above). JCT: Portion of stipend through an NIH training grant (see above). CGB: None. JDB: Scientific advisory board member for CVRx and clinical research support from CVRx. KAI: Scientific advisory board member for CVRx and clinical research support from CVRx.
Supporting information
Figure S1. Decision Tree.
Figure S2. State transition diagram.
Table SI. (A) Prevalence values used for the Framingham prediction equations. (B) Relative risk for developing end‐stage renal disease (ESRD) with various systolic blood pressures (SBP). (C) ESRD mortality by age. (D) Prevalence of atrial fibrillation by age and gender.
Please note: Wiley‐Blackwell are not responsible for the content or functionality of any supporting materials supplied by the authors. Any queries (other than missing material) should be directed to the corresponding author for the article.
Supporting info item
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Associated Data
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Supplementary Materials
Figure S1. Decision Tree.
Figure S2. State transition diagram.
Table SI. (A) Prevalence values used for the Framingham prediction equations. (B) Relative risk for developing end‐stage renal disease (ESRD) with various systolic blood pressures (SBP). (C) ESRD mortality by age. (D) Prevalence of atrial fibrillation by age and gender.
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