Formulary management of ACE inhibitors

Research trends in contemporary health economics: a scientometric analysis on collective content of specialty journals

INTRODUCTION

Health economics is a thriving sub-discipline of economics. Applied health economics research is considered essential in the health care sector and is used extensively by public policy makers. For scholars, it is important to understand the history and status of health economics-when it emerged, the rate of research output, trending topics, and its temporal evolution-to ensure clarity and direction when formulating research questions.

METHODS

Nearly 13,000 articles were analysed, which were found in the collective publications of the ten most specialised health economic journals. We explored this literature using patterns of term co-occurrence and document co-citation.

RESULTS

The research output in this field is growing exponentially. Five main research divisions were identified: (i) macroeconomic evaluation, (ii) microeconomic evaluation, (iii) measurement and valuation of outcomes, (iv) monitoring mechanisms (evaluation), and (v) guidance and appraisal. Document co-citation analysis revealed eighteen major research streams and identified variation in the magnitude of activities in each of the streams. A recent emergence of research activities in health economics was seen in the Medicaid Expansion stream. Established research streams that continue to show high levels of activity include Child Health, Health-related Quality of Life (HRQoL) and Cost-effectiveness. Conversely, Patient Preference, Health Care Expenditure and Economic Evaluation are now past their peak of activity in specialised health economic journals. Analysis also identified several streams that emerged in the past but are no longer active.

CONCLUSIONS

Health economics is a growing field, yet there is minimal evidence of creation of new research trends. Over the past 10 years, the average rate of annual increase in internationally collaborated publications is almost double that of domestic collaborations (8.4% vs 4.9%), but most of the top scholarly collaborations remain between six countries only.

Renin-angiotensin-aldosterone pathway modulators in chronic kidney disease: A comparative review

Chronic kidney disease presents a health challenge that has a complex underlying pathophysiology, both acquired and inherited. The pharmacotherapeutic treatment options available today lower the progression of the disease and improve the quality of life but cannot completely cure it. This poses a challenge to the healthcare provider to choose, from the available options, the best way to manage the disease as per the presentation of the patient. As of now, the recommended first line of treatment to control the blood pressure in chronic kidney disease is the administration of renin-angiotensin-aldosterone system modulators. These are represented mainly by the direct renin inhibitor, angiotensin-converting enzyme inhibitors, and angiotensin II receptor blockers. These modulators are varied in their structure and mechanisms of action, hence showing varying treatment outcomes. The choice of administration of these modulators is determined by the presentation and the co-morbidities of the patient, the availability and affordability of the treatment option, and the expertise of the healthcare provider. A direct head-to-head comparison between these significant renin-angiotensin-aldosterone system modulators is lacking, which can benefit healthcare providers and researchers. In this review, a comparison has been drawn between the direct renin inhibitor (aliskiren), angiotensin-converting enzyme inhibitors, and angiotensin II receptor blockers. This can be of significance for healthcare providers and researchers to find the particular loci of interest, either in structure or mechanism, and to intervene as per the case presentation to obtain the best possible treatment option.

Hypertension and common complications --analysis of the ambulatory treatment cost

AIM

Retrospective analysis of the prescribing practice and cost of ambulatory treatment of hypertension and its common complications--heart failure, sequelae of cerebrovascular disease, and angina pectoris.

METHODS

Analysis of 3,240 reimbursable ambulatory prescriptions for hypertension, heart failure, sequelae of cerebrovascular disease and angina pectoris according to the complexity of the therapy and frequency of the prescribed medicines. Modeling and calculation of the expected monthly cost for outpatient therapy by using the "decision tree model". Sensitivity analysis is performed within the +/- 30% interval.

RESULTS

65% of the prescription were for the hypertension, and 35% for the observed complications. 1,297 prescriptions for hypertension include one medicine, 647 include two medicines, and only 8% of prescriptions were for three medicines. ACE inhibitors have been prescribed in 41% of all hypertension prescriptions, followed by beta-blockers (19%), Ca channel blockers (16%), diuretics (15%) etc. The prescriptions for hypertension complications are more diverse as therapeutic groups. The expected monthly cost of prescribed medicines per patient with hypertension alone is 6.90 Euro and in case of complications it is 10.71 Euro according to the prevalence of the complexity of therapy, and weighted monthly cost of medicines. The overall ambulatory cost is expected to be around 148 million Euro per year for near 1.5 million patients with 44% reimbursement. The cost of the therapy is sensitive more to changes in the medicine's prices than to its complexity.

CONCLUSION

This study is a first step in providing information for evidence-based cost containment measures or policy decisions at ambulatory level in Bulgaria and for the assessment of the share of complications' therapy on the overall hypertension cost.

Cost-effective strategies in the prevention of diabetic nephropathy

A significant subgroup of patients with diabetes mellitus are predisposed to developing diabetic nephropathy and it is in this subgroup that other diabetes- related complications, and in particular greatly increased cardiovascular disease risk, are concentrated. The high personal, social and financial costs of managing end-stage renal failure and the other complications associated with diabetic nephropathy make a powerful case for screening and effective intervention programmes to prevent the condition or retard its progression. As major breakthroughs in finding genetic susceptibility factors remain elusive, screening efforts continue to be based on microalbuminuria testing, despite increasing recognition of its limitations as a positive predictor of nephropathy. Interventions have been extensively studied, but results remain conflicting. Economic evaluations of such screening and intervention programmes are essential for health planners, yet models of the cost/benefit ratio of such interventions often rely on a rather slim evidence base. Where economic models are developed, they are frequently based on those papers that propound the greatest clinical benefits of a given intervention, leading to a possible over-estimation of the advantages of the chosen approach. Furthermore, the benefits of even such generally accepted interventions as ACE inhibitor treatment are less firmly established than generally appreciated. Lifestyle interventions are instinctively attractive, but are by no means a low-cost option (as is often assumed by both medical professionals and politicians). This review critically assesses the evidence for clinical efficacy and economic benefit of microalbuminuria screening and interventions such as intensive glycaemic control, antihypertensive treatment, ACE inhibition and angiotensin receptor blockade, dietary protein restriction and lipid-modifying therapy. The various costs associated with diabetic nephropathy are so great that even expensive interventions may have a favourable cost/benefit ratio, provided they are truly effective.

Are cholesterol-lowering medications and antihypertensive agents preventing stroke in ways other than by controlling the risk factor?

Statins and angiotensin-converting enzyme (ACE) inhibitors are an important component of our armamentarium for stroke prevention. Both of these classes of agents have a primary mechanism of action of reducing the level of the respective risk factor. They also have mechanisms of action that may confer benefits beyond what is believed to be the primary action of the agent. This has led to speculation that statins reduce stroke risk by means beyond cholesterol lowering, and ACE inhibitors reduce stroke risk by means beyond blood pressure lowering. We review the mounting evidence that suggests that statins and ACE inhibitors have so-called pleiotropic effects that may lead to stroke prevention.

Are cholesterol-lowering medications and antihypertensive agents preventing stroke in ways other than by controlling the risk factor?

Statins and angiotensin-converting enzyme (ACE) inhibitors are an important component of our armamentarium for stroke prevention. Both of these classes of agents have a primary mechanism of action of reducing the level of the respective risk factor. They also have mechanisms of action that may confer benefits beyond what is believed to be the primary action of the agent. This has led to speculation that statins reduce stroke risk by means beyond cholesterol lowering, and ACE inhibitors reduce stroke risk by means beyond blood pressure lowering. We review the mounting evidence that suggests that statins and ACE inhibitors have so-called pleiotropic effects that may lead to stroke prevention.

New horizons for stroke prevention: PROGRESS and HOPE

Inhibitors of angiotensin-converting enzyme (ACE) act by blocking the conversion of angiotensin I to angiotensin II, which is catalysed by this enzyme. ACE inhibitors also prevent the breakdown of bradykinin, a potent vasodepressor agent, and prevent the effects of angiotensin II, which include increase in blood pressure, peripheral vasoconstriction, and stimulation of aldosterone secretion from the adrenal cortex. Physiological and pathological studies have shown that ACE inhibitors have beneficial effects, such as increasing vascular compliance, regression of periarteriolar collagen area, improvement of coronary reserve, and regression of resistance-artery structure and left-ventricular hypertrophy. Information about the role of ACE inhibitors in stroke prevention has been limited. This review explores the epidemiological evidence for hypertension as a risk factor for stroke, a national guideline for blood-pressure control to reduce the incidence of stroke and cardiovascular disease, the findings of two recently published clinical trials on prevention of stroke and cardiovascular disease after administration of ACE inhibitors (PROGRESS and HOPE), and the implications of the findings for redefinition of future management of blood-pressure control for individuals at high risk of stroke and cardiovascular disease. The PROGRESS and HOPE trials have shown that ACE inhibitors have an important role in the prevention of stroke and cardiovascular-disease events.

Pharmacoeconomic considerations in assessing and selecting congestive heart failure therapies

Over the last two decades the incidence of congestive heart failure (CHF) has increased with aging of the population and in spite of the decline in age-adjusted mortality rates due to coronary heart disease. Its management has seen substantial progress, embodied in the introduction of ACE inhibitors, initially as part of triple therapy in which they complemented diuretics and digoxin, and latterly as first-line therapy. The current consensus on treatment of CHF has been based on the multiple clinical studies performed with ACE inhibitors in which these agents have been shown to prevent a new cardiovascular accident and/or progression to more severe CHF in an increasingly wide range of patients with symptomatic CHF or post-infarction left ventricular dysfunction (ejection fraction </= 40% in some trials or </= 35% in others). Not only have the results shown a marked decrease in all-cause (and especially cardiovascular) mortality, but also a great number of cost-effectiveness analyses have shown the advantages of ACE inhibitors in terms of resource allocation: they are either cost saving or convincingly cost effective compared with standard treatment with digoxin and diuretics. Other drugs require similar cost and clinical analyses before they can earn their place in an add-on strategy. To date, cost savings have been documented only for beta-blockers; implantable devices are still undergoing assessment. Two trends are now competing: one is to downplay add-on strategies and to recommend first-line therapy with ACE inhibitors and beta-blockers at effective doses, supplemented by a raft of non-pharmaceutical measures (specialist nurses, patient education, dietary advice, exercise) in a multidisciplinary approach to CHF; the second is, on the contrary, to prescribe up to five drugs for patients with advanced CHF. The evidence that this decreases hospital admission rates and patient cost is more than anecdotal, but conclusive proof of cost effectiveness is still lacking and the approach presupposes dedicated structures. This review argues that despite technical limitations, a combined approach of CHF therapy based on clinical trials and cost-effectiveness analyses is essential. However, improvements can be made. The absence of sufficient comparative data still makes it difficult to choose between drugs within the same class; institutional purchasers need to conduct such analyses to identify the drugs best suited to their patients' profiles and budgetary constraints.

Perindopril: an updated review of its use in hypertension

Perindopril erbumine (perindopril) is a prodrug ester of perindoprilat, an angiotensin converting enzyme (ACE) inhibitor. Perindopril 4 to 8 mg once daily significantly reduces supine systolic blood pressure (SBP) and diastolic blood pressure (DBP) from baseline values in hypertensive patients. These reductions are maintained for at least 24 hours, as evidenced by trough/peak ratios of >50%. Vascular abnormalities associated with hypertension were improved or normalised during perindopril treatment. Perindopril 4 to 8 mg once daily significantly decreased carotid-femoral aortic pulse wave velocity (PWV), improved arterial compliance, reduced left ventricular mass index and, in patients with recent cerebral ischaemia and/or stroke, preserved cerebral blood flow despite significantly reducing SBP and DBP. Further research is needed to establish the significance of promising results showing that reductions in aortic PWV were associated with reduced mortality in patients with end-stage renal failure, a third of whom received perindopril. Response rates (numbers of patients with supine DBP < or = 90 mm Hg) were significantly higher with perindopril 4 to 8 mg once daily (67 to 80%) than with captopril 25 to 50 mg twice daily (44 to 57%) in 3 randomised double-blind trials. In other clinical trials, the antihypertensive effects of perindopril were similar to those of other ACE inhibitors (including enalapril) and calcium-channel antagonists. Combination treatment with perindopril and an antihypertensive agent from another treatment class provided additional benefits, either as first-line treatment or in patients failing to respond to monotherapy. Perindopril monotherapy was also effective in the elderly and in patients with hypertension and concomitant disease. Perindopril has a similar adverse event profile to that of other ACE inhibitors; cough is the most common event reported during treatment, and is also the most common adverse event responsible for treatment withdrawal.

CONCLUSIONS

Perindopril is a well tolerated ACE inhibitor that is significantly better than captopril (in terms of response rates) in the treatment of hypertension, and as effective as other ACE inhibitors. Perindopril appears to reverse some of the vascular abnormalities associated with hypertension, including arterial stiffness and left ventricular hypertrophy, although further research is needed to confirm promising results regarding its ability to decrease associated cardiovascular morbidity and mortality. Results from ongoing studies will help confirm the place of perindopril in the treatment of hypertension; currently, it is an effective and well tolerated treatment for patients with mild to moderate essential hypertension.

Capillary zone electrophoresis applied to the determination of the angiotensin-converting enzyme inhibitor cilazapril and its active metabolite in pharmaceuticals and urine

A capillary zone electrophoresis method has been developed for the quantitation of antihypertensive drug cilazapril and its active metabolite cilazaprilat in pharmaceuticals and urine. The separation of the compounds was performed in a fused-silica capillary filled with the running electrolyte, which consisted of a 60 mM borate buffer solution at pH 9.5. Under the optimized experimental conditions, the separation took less than 5 min. The analysis of urine samples required a previous solid-phase extraction step using C8 cartridges. The method was successfully applied to the determination of the drug and its metabolite in urine samples obtained from three hypertensive patients (detection limits of 115 ng ml(-1) for cilazaprilat and 125 ng ml(-1) for cilazapril) and to pharmaceutical dosage forms. The method was validated in terms of reproducibility, linearity and accuracy.