Within the health sector, innovation is the key to progress in scientific research, patient care, and business-related concerns. Nonetheless, the introduction of new medical technology should provide substantial added value in regular clinical practice. For this reason, the Spanish Society of Cardiology (Sociedad Española de Cardiología [SEC]) has implemented the strategic initiative, InnovaSEC, to analyze the value of new technology contemplated for use in the Spanish health care setting.1 The first new product evaluated under the auspices of InnovaSEC is the Barostim medical device.

Barostim (CVRx Inc., Minneapolis, Minnesota, United States) is an implantable system that lowers blood pressure by electrical stimulation of the carotid baroreceptors. It is indicated as a second-line treatment for hypertensive patients resistant to conventional medical therapy (established on systolic blood pressure [SBP] values ≥ 140mmHg, despite the use of at least 3 antihypertensive drugs, including a diuretic). Refractory hypertension affects 0.3% of hypertensive Spanish patients.2 Considering that the prevalence of hypertension in the Spanish population older than 30 years is around 30%,3 there would be approximately 29 000 patients with hypertension refractory to drug therapy in Spain.

Carotid baroreceptor stimulation is considered a possible therapeutic option for refractory hypertension in the guidelines of the European Society of Hypertension and the European Society of Cardiology.4 Furthermore, the indication for Barostim in patients refractory to conventional treatment was found to be cost-effective for the German population (cost-effectiveness ratio, 7797 euros/quality-adjusted life year [QALY]).5 However, the epidemiologic profile of the Spanish population and the cost of treating hypertension and its complications in Spain differ from those observed in northern European countries, and both these variables could have a considerable impact on the cost-effectiveness of this technology in our country.

The aim of this study was to analyze the cost-effectiveness of Barostim as a second-line treatment compared with an adequate pharmacologic regimen (at least 3 antihypertensive drugs, including a diuretic agent) in the population of adults with hypertension (SBP ≥ 140mmHg), from the perspective of the publically-funded Spanish Health System.

Barostim lowered the probability of experiencing all the adverse events considered (Table 5). The probability of having a first CVA decreased by 0.078 points, representing a 33.2% drop in the number of cases compared with those occurring with optimal drug therapy. Recurrent CVAs decreased by 37.6%. The probability of having a first AMI fell by 0.029 points, implying a 14.7% reduction in the number of cases. Recurrent AMI decreased by 19.7%. Cases of ischemic heart disease and heart failure fell by approximately 13.5%. Finally, cases of end-stage renal disease decreased by 15.7%.

Patients treated with drug therapy alone obtained 14.92 QALYs, whereas those treated with Barostim reached 15.7 QALYs; that is, an increase of 0.78 QALY per patient (Table 6).

The average direct cost per patient receiving drug therapy was 23 098 euros, whereas the cost per patient with Barostim was 76 466 euros. The indirect costs were 23 223 euros and 20 301 euros, respectively. Considering both types of costs (direct plus indirect), the incremental cost of Barostim compared with pharmacologic therapy was 50 446 euros per patient.

The ICER of Barostim relative to drug therapy without considering indirect costs was 68 726 euros per QALY. Considering indirect costs, the ICER of Barostim vs pharmacologic therapy was 64 963 euros per QALY. The component that had the greatest weight in the incremental cost was the expenditure associated with replacement of the Barostim battery.

When the model was applied in a cohort of women, the Barostim device resulted in an increase of 0.54 QALY. The direct incremental cost was 60 242 euros and the ICER increased to 111 337 euros per QALY. Considering indirect costs, the ICER was estimated at 107 241 euros per QALY.

Sensitivity Analysis

In the deterministic sensitivity analysis, the variables with the strongest impact on the ICER were the initial SBP, the effectiveness of Barostim starting from 3 years following implantation, smoker status, and the initial patient age. The deterministic sensitivity analysis showed that none of the parameters studied substantially modified the ICER (Figure 2).

Figure 2.

Results of the deterministic sensitivity analysis. AMI, acute myocardial infarction; CVA, cerebrovascular accident; ESRD, end-stage renal disease; HF, heart failure; HDL-C, high-density lipoprotein cholesterol; IHD, ischemic heart disease; QALY, quality-adjusted life year; PT, pharmacologic therapy.

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The probabilistic sensitivity analysis indicated that the probability of Barostim being cost-effective at a threshold of 30 000 euros per QALY was close to 0% (Figure 3). When the willingness to pay was raised to 100 000 euros/QALY, the probability increased to 80% in men and 25% in women. The cost-effectiveness scatter plot (Figure 4) shows that Barostim produced an increase in the number of QALYs and had an incremental cost of at least 40 000 euros per patient in all cases.

Figure 3.

Incremental cost-effectiveness ratio acceptability curve. QALY, quality-adjusted life year.

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Figure 4.

Cost-effectiveness scatter plot and 95% confidence ellipse. A: men. B: women. QALY, quality-adjusted life year.

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This study provides the first economic assessment of the Barostim medical device adapted to the health and social setting of Spain. The results indicate that Barostim use would contribute to a reduction in cardiovascular events in the study population. The number of AMI, CVA, and end-stage renal disease occurring in the study cohort would decrease by 15.2%, 34.2%, and 15.7%, respectively. The number of QALY would increase by 0.78% relative to treatment with drug therapy. However, this positive impact was associated with considerable expenditure: an incremental direct cost of 53 000 euros per patient receiving the device. Thus, the ICER of Barostim compared with drug therapy was close to 69 000 euros per QALY without considering indirect costs, or approximately 65 000 euros per QALY including indirect costs. In Spain, the informal cost-effectiveness threshold is estimated at 30 000 euros per QALY.44 Therefore, the cost of Barostim is high in relation to the health benefits that would be obtained in the Spanish health care setting. The ICER is also much higher than the value reported in the single published article on this topic, which analyzed the cost-effectiveness of Barostim in the German health system.5 Health care costs and indirect costs are lower in Spain than in Germany and because of this factor, Barostim use would enable smaller reductions in these costs in our country, partially explaining this difference.

The high ICER found in the present study also results from the relatively small increase in the number of QALYs associated with Barostim use. While it is true that the reduction in adverse cardiac events is considerable when measured in percent terms, the decrease is relatively moderate when viewed in absolute terms. Our estimates indicate that 3.3 AMI, 10.4 CVA, and 1.1 end-stage renal disease cases would be averted per each 100 patients receiving a Barostim device. These values are considerably lower than those reported by Borisenko et al5 in the German study, citing estimated reductions of 5.1 AMI, 12 CVA, and 2.3 end-stage renal disease cases per each 100 patients with the device. The main explanation for these differences is the lower incidence of cardiac and cerebrovascular diseases in hypertensive patients in Spain relative to their northern European counterparts. For example, according to the REGICOR10 study, an individual with the characteristics used in our study would have a 7.6% 10-year probability of experiencing coronary disease (ischemic heart disease or AMI). In the study by Borisenko et al using the Framingham equations,45 the estimated probability would be between 20% and 25%. Similarly, the risk of CVA (as a first event) in the base cohort over a 10-year horizon would be 4.4% according to the FRESCO11 study but would be 11% according to the Framingham equations for CVA.46

One factor that has a substantial impact on the cost of Barostim is the need for battery replacement throughout the patient's lifetime. Our estimates indicate that this accounts for almost 50% of the total direct cost. This finding can be explained by the current price of the battery, which requires replacement every 6 years. When this expenditure is omitted, the ICER would drop to 22 982 euros per QALY. Thus, the ICER would be decreased by future reductions in the cost of the batteries or improvements in their service life.

One of the main limitations of this study is the lack of robust information on the effectiveness of Barostim in periods longer than 3 years. The data on the long-term effectiveness of the device (ie, to the end of the patient's life) included in the analysis were based on a report showing a decrease of 35 mmHg after a mean follow-up of 2.3 years.43

Second, costs related to possible adverse effects associated with Barostim were not included in the calculations. The adverse effects identified were related to implantation of the device and included permanent nerve damage (4.8%), temporary nerve injury (4.4%), and other surgical complications (4.8%).30 If these events had been incorporated in the model, the ICER of Barostim would have been higher.

Lastly, as there are no studies on heart failure risk in the Spanish population, this factor was measured using the original Framingham equations.12 Hence, the predicted number of heart failure cases and associated adverse events may have been overestimated in our model.

Although Barostim is effective in reducing SBP and progression to undesirable health states in the short term, based on the current prices and considering a willingness to pay of 30 000 euros per QALY, it is not a cost-effective option for treating the hypertensive population refractory to drug therapy in the Spanish health care setting.

This study was partially funded by the SEC. M. Soto received support from the Plataforma de Innovación en Tecnologías Médicas y Sanitarias, PT13/0006/0009 project (Fundació Clínic per a la Recerca Biomèdica, PI043029).

J. Brugada is a consultant on the CVRx Scientific Committee.