Economic evaluation of four angiotensin II receptor blockers in the treatment of hypertension

Improving Adherence to Treatment and Reducing Economic Costs of Hypertension: The Role of Olmesartan-Based Treatment

Poor adherence to antihypertensive treatment is the single most important factor of unsatisfactory blood pressure (BP) control. This review focuses on therapy-related factors affecting adherence and suggests how to improve it with a wise choice of treatment schedule. Complex drug treatment schemes, poor tolerability and drug substitutions are frequent causes of poor adherence which, in turn, causes insufficient BP control, greater incidence of cardiovascular events and, finally, higher global health costs. The effects of prescribing generic drugs and of drug substitutions on adherence is also discussed. In terms of adherence, generic drugs do not seem to be better than branded drugs, unless patients have to bear very high "out of pocket" expenses to buy original drugs, suggesting no advantages in switching drug with the mere goal of reducing the cost of therapy. An important role in improving adherence (and thus cardiovascular events and health expenditure) is also played by the availability of fixed-dose combinations; among antihypertensive drugs, angiotensin receptor blockers (ARBs) are those associated with higher levels of adherence and persistence. Among ARBs, olmesartan stands out for a wide choice of effective fixed-dose combinations.

A literature review to evaluate the clinical and economic value of olmesartan for the treatment of hypertensive patients

The objective of the present study was to systematically review the clinical and economic outcomes of olmesartan as monotherapy or in combination with other antihypertensive agents in the treatment of hypertension. A literature search was performed using PubMed and the Cochrane library until December 2015, with no limit on publication date. Eligible studies were selected using predetermined inclusion and exclusion criteria, limiting articles to those published in the English language. Background information of the study, participants' characteristics and study outcomes were collected. Meta-analysis of data was not performed. Fifty-five studies were included, of which fifty investigated the clinical efficacy of olmesartan and five the cost-effectiveness of olmesartan. In general results from clinical trials evaluating the efficacy of olmesartan as monotherapy and as combination therapy demonstrated that olmesartan provided better antihypertensive blood pressure-lowering efficacy and was generally well tolerated compared with other antihypertensive agents. Results from economic evaluations indicated that olmesartan may be more cost-effective than other ARBs such as losartan, valsartan, irbesartan and candesartan, having the potential of decreasing the overall medical costs of care for patients with hypertension. Evidence from the present systematic review confirms the antihypertensive efficacy and good safety profile of olmesartan both as monotherapy and as combination therapy. Olmesartan was also found to be cost-effective compared with other ARBs, though this area has yet relatively poor evidence and needs to further be explored.

Economic evaluation for first-line anti-hypertensive medicines: applications for the Philippines

BACKGROUND

Medicines to control hypertension, a leading cause of morbidity and mortality, are a major component of health expenditures in the Philippines. This study aims to review economic studies for first line anti-hypertensive medical treatment without co-morbidities; and discuss practical, informational and policy implications on the use of economic evaluation in the Philippines.

METHODS

A systematic literature review was performed using the following databases: MEDLINE, EMBASE, BIOSIS, PubMed, The Cochrane Library, Health Economics Evaluations Database (HEED) and the Centre for Reviews and Dissemination - NHS NICE. Six existing economic analytical frameworks were reviewed and one framework for critical appraisal was developed.

RESULTS

Out of 1336 searched articles, 12 fulfilled the inclusion criteria. The studies were summarized according to their background characteristics (year, journal, intervention and comparators, objective/study question, target audience, economic study type, study population, setting and country and source of funding/conflict of interest) and technical characteristics (perspective, time horizon, methodology/modeling, search strategy for parameters, costs, effectiveness measures, discounting, assumptions and biases, results, cost-effectiveness ratio, endpoints, sensitivity analysis, generalizability, strengths and limitations, conclusions, implications and feasibility and recommendations). The studies represented different countries, perspectives and stakeholders.

CONCLUSIONS

Diuretics were the most cost-effective drug class for first-line treatment of hypertension without co-morbidities. Although the Philippine Health Insurance Corporation may apply the recommendations given in previous studies (i.e. to subsidize diuretics, ACE inhibitors and calcium channel blockers), it is uncertain how much public funding is justified. There is an information gap on clinical data (transition probabilities, relative risks and risk reduction) and utility values on hypertension and related diseases from middle- and low- income countries. Considering the national relevance of the disease, a study on the costs of hypertension in the Philippines including in-patient, out-patient, out-of-pocket, local government and national government expenditure must be made. Economic evaluation may be incorporated in health technology assessment, planning, proposal development, research, prioritization and evaluation of health programmes. The approaches will vary depending on the policy questions. The information gap calls for building strong economic evaluative capacity in growing economies.

Comparative effectiveness analysis of amlodipine/renin-angiotensin system blocker combinations

A comparative effectiveness analysis of antihypertensive therapy amlodipine (AML) and angiotensin receptor blocker (ARB) fixed- and loose-dose combinations (FDCs and LDCs) in achieving blood pressure (BP) reduction and Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure (JNC 7) goal attainment was made using retrospective electronic medical record (EMR) data. Treatment goal rates ranged from 35.0% for LDC AML/losartan to 45.7% for FDC AML/olmesartan (OM). FDC AML/OM achieved significantly greater reductions in systolic BP than FDC AML/benazepril (BEN), FDC AML/valsartan (VAL), and LDC AML/ARBs, respectively, and significantly greater reductions in diastolic BP than FDC AML/VAL and LDC therapy, respectively. Compared with patients treated with AML/OM, patients prescribed AML/VAL and LDC AML/ARB were significantly less likely to attain JNC 7 BP goal. Among subpopulations, AML/OM yielded higher rates of goal attainment among both African Americans and obese/overweight patients relative to AML/VAL and combined LDCs. Switchers from monotherapy with AML, OM, or VAL to AML/OM were significantly more likely to attain JNC 7 goals than those switching to AML/VAL or AML/BEN.

A cost-utility analysis of hypertension treatment in Greece: assessing the impact of age, sex and smoking status, on outcomes

OBJECTIVES

To assess the cost-utility of hypertension treatment versus a hypothetical 'no-treatment' strategy in Greece.

METHODS

A six-state Markov model simulated the occurrence of major cardiovascular events for hypertensive patients over a 20-year period. Baseline population consisted of a cohort of 1453 patients (46.92% men) that were followed up for a 1-year period, during which health-resource use and clinical characteristics of hypertension were documented. Age, sex and smoking status - specific transition probabilities in the model - were estimated via the HellenicSCORE and Framingham risk equations. The analysis followed a third-party payer perspective.

RESULTS

Incremental cost-effectiveness ratios (ICERs) of treatment versus no treatment were 3539&OV0556;/quality-adjusted life year (QALY), 3986&OV0556;/QALY, 3957&OV0556;/QALY and 5485&OV0556;/QALY gained for men smokers, men nonsmokers, women smokers and women nonsmokers, respectively. ICERs became more favorable with an increase in the years of treatment and advanced age of treatment initiation across all study groups. The probabilistic sensitivity analysis showed that the base-case scenario results were cost-effective for an implicit 30 000&OV0556;/QALY threshold at 97.4, 95.2, 94.8, and 86% of the 10 000 Monte Carlo simulations for men smokers, men nonsmokers, women smokers and women nonsmokers, respectively.

CONCLUSION

In the case of hypertension, one of the most prevalent and modifiable diseases/risk factors, that is accompanied by large-scale costs, the above analysis demonstrates that treatment is a highly cost-effective intervention that should be further supported at the patient and the system level.

Evolutionary cost analysis of valsartan initiation among patients with hypertension: a time series approach

OBJECTIVES

This study examines the evolutionary impact of valsartan initiation on medical costs.

METHODS

A retrospective time series study design was used with a large, US national commercial claims database for the period of 2004-2008. Hypertensive patients who initiated valsartan between the ages of 18 and 63, and had continuous enrollment for 24-month pre-initiation period and 24-month post-initiation period were selected. Patients' monthly medical costs were calculated based on individual claims. A novel time series model was devised with monthly medical costs as its dependent variables, autoregressive integrated moving average (ARIMA) as its stochastic components, and four indicative variables as its decomposed interventional components. The number of post-initiation months before a cost-offset point was also assessed.

RESULTS

Patients (n = 18,269) had mean age of 53 at the initiation date, and 53% of them were female. The most common co-morbid conditions were dyslipidemia (52%), diabetes (24%), and hypertensive complications (17%). The time series model suggests that medical costs were increasing by approximately $10 per month (p < 0.01) before the initiation, and decreasing by approximately $6 per month (p < 0.01) after the initiation. After the 4th post-initiation month, medical costs for patients with the initiation were statistically significantly lower (p < 0.01) than forecasted medical costs for the same patients without the initiation.

LIMITATIONS

The study has its limitations in data representativeness, ability to collect unrecorded clinical conditions, treatments, and costs, as well as its generalizability to patients with different characteristics.

CONCLUSIONS

Commercially insured hypertensive patients experienced monthly medical cost increase before valsartan initiation. Based on our model, the evolutionary impact of the initiation on medical costs included a temporary cost surge, a gradual, consistent, and statistically significant cost decrease, and a cost-offset point around the 4th post-initiation month.

Long-term clinical and economic outcomes associated with angiotensin II receptor blocker use in hypertensive patients

OBJECTIVE

To examine clinical and economic outcomes associated with angiotensin II receptor blockers (ARB).

METHODS

Retrospective claims data were analyzed for hypertensive adults with ≥1 year follow-up from first ARB claim. Subjects were stratified into four cohorts: olmesartan (OM); valsartan (VAL); losartan (LOS); and irbesartan (IRB), which represented the full sample. Analyses were also conducted with the "limited sample," which excluded subjects with pre-existing conditions in the period before first ARB. Time to follow-up cardiac event was modeled using Cox proportional hazards regression; follow-up healthcare resource utilization and costs were examined using generalized linear models.

RESULTS

The full and limited samples consisted of 118,700 and 65,579 subjects, respectively. Mean follow-up ranged from 861 to 933 days. Baseline characteristics including the Quan-Charlson comorbidity score differed by cohort. In both the full and limited samples, respectively, multivariate models predicted a higher adjusted risk of follow-up cardiac event for VAL cohort (hazard ratio [HR] = 1.261 and 1.242, p < 0.001), LOS cohort (HR = 1.307 and 1.178, p < 0.01), and IRB cohort (HR = 1.222 and 1.179, p ≤ 0.016) compared to OM cohort. Adjusted risk (full sample) of follow-up ambulatory and inpatient visits (all-cause and hypertension-attributable) was higher in VAL, LOS, and IRB cohorts compared to OM. Adjusted risk (limited sample) of follow-up ambulatory visits (all-cause and hypertension-attributable) was greater for VAL, LOS and IRB cohorts relative to OM, but inpatient visit risk was greater only in VAL and LOS cohorts. Compared to the OM cohort, follow-up all-cause adjusted healthcare costs (limited sample) were higher in VAL (cost ratio [CR] = 1.067, p = 0.001) and IRB cohorts (CR = 1.062, p = 0.045).

CONCLUSIONS

In this large national US health plan, treatment with OM was associated with lower risk of cardiac events and lower healthcare resource utilization and costs versus VAL, LOS, and IRB over a mean follow-up of 2.5 years. Association, rather than causality, to cardiac outcomes may be inferred from these observational claims data.