Pharmacoeconomics of angiotensin II antagonists in type 2 diabetic patients with nephropathy: implications for decision making

Losartan, an Angiotensin II Type 1 Receptor Antagonist, Alleviates Mechanical Hyperalgesia in a Rat Model of Chemotherapy-Induced Neuropathic Pain by Inhibiting Inflammatory Cytokines in the Dorsal Root Ganglia

Chemotherapy-induced peripheral neuropathy (CIPN) adversely impacts quality of life and a challenge to treat with existing drugs used for neuropathic pain. Losartan, an angiotensin II type 1 receptor (AT1R) antagonist widely used to treat hypertension, has been reported to have analgesic effects in several pain models. In this study, we assessed losartan's analgesic effect on paclitaxel-induced neuropathic pain (PINP) in rats and its mechanism of action in dorsal root ganglion (DRG). Rats received intraperitoneal injections of 2 mg/kg paclitaxel on days 0, 2, 4, and 6 and received single or multiple intraperitoneal injections of losartan potassium dissolved in phosphate-buffered saline at various times. The mechanical thresholds, protein levels of inflammatory cytokines, and cellular location of AT1R and interleukin 1β (IL-1β) in the DRG were assessed with behavioral testing, Western blotting, and immunohistochemistry, respectively. Data were analyzed by two-way repeated-measures analysis of variance for the behavioral test or the Mann-Whitney U test for the Western blot analysis and immunohistochemistry. Single and multiple injections of losartan ameliorated PINP, and losartan delayed the development of PINP. Paclitaxel significantly increased, and losartan subsequently decreased, the expression levels of inflammatory cytokines, including IL-1β and tumor necrosis factor α (TNF-α), in the lumbar DRG. AT1R and IL-1β were expressed in both neurons and satellite cells and losartan decreased the intensity of IL-1β in the DRG. Losartan ameliorates PINP by decreasing inflammatory cytokines including IL-1β and TNF-α in the DRG. Our findings provide a new or add-on therapy for CIPN patients.

Budget impact analysis of increasing prescription of renin-angiotensin system inhibitors drugs to standard anti-hypertensive treatments in patients with diabetes and hypertension in a hypothetical cohort of Malaysian population

INTRODUCTION

Renin-angiotensin system inhibitors (RAS) drugs have a proteinuria-reducing effect that could prevent the progression of kidney disease in diabetic patients. Our study aimed to assess the budget impact based on healthcare payer perspective of increasing uptake of RAS drugs into the current treatment mix of standard anti-hypertensive treatments to prevent progression of kidney disease in patient's comorbid with hypertension and diabetes.

METHODS

A Markov model of a Malaysian hypothetical cohort aged ≥30 years (N = 14,589,900) was used to estimate the total and per-member-per-month (PMPM) costs of RAS uptake. This involved an incidence and prevalence rate of 9.0% and 10.53% of patients with diabetes and hypertension respectively. Transition probabilities of health stages and costs were adapted from published data.

RESULTS

An increasing uptake of RAS drugs would incur a projected total treatment cost ranged from MYR 4.89 billion (PMPM of MYR 27.95) at Year 1 to MYR 16.26 billion (PMPM of MYR 92.89) at Year 5. This would represent a range of incremental costs between PMPM of MYR 0.20 at Year 1 and PMPM of MYR 1.62 at Year 5. Over the same period, the care costs showed a downward trend but drug acquisition costs were increasing. Sensitivity analyses showed the model was minimally affected by the changes in the input parameters.

CONCLUSION

Mild impact to the overall healthcare budget has been reported with an increased utilization of RAS. The long-term positive health consequences of RAS treatment would reduce the cost of care in preventing deterioration of kidney function, thus offsetting the rising costs of purchasing RAS drugs. Optimizing and increasing use of RAS drugs would be considered an affordable and rational strategy to reduce the overall healthcare costs in Malaysia.

KRAS mutant colorectal cancer gene signatures identified angiotensin II receptor blockers as potential therapies

Colorectal cancer (CRC) is a life-threatening disease with high prevalence and mortality worldwide. The KRAS oncogene is mutated in approximately 40% of CRCs. While antibody based EGFR inhibitors (cetuximab and panitumumab) represent a major treatment strategy for advanced KRAS wild type (KRAS-WT) CRCs, there still remains no effective therapeutic course for advanced KRAS mutant (KRAS-MT) CRC patients.In this study, we employed a novel and comprehensive approach of gene expression connectivity mapping (GECM) to identify candidate compounds to target KRAS-MT tumors. We first created a combined KRAS-MT gene signature with 248 ranked significant genes using 677 CRC clinical samples. A series of 248 sub-signatures was then created containing an increasing number of the top ranked genes. As an input to GECM analysis, each sub-signature was translated into a statistically significant therapeutic drugs list, which was finally combined to obtain a single list of significant drugs.We identify four antihypertensive angiotensin II receptor blockers (ARBs) within the top 30 significant drugs indicating that these drugs have a mechanism of action that can alter the KRAS-MT CRC oncogenic signaling. A hypergeometric test (p-value = 6.57 × 10-6) confirmed that ARBs are significantly enriched in our results. These findings support the hypothesis that ARB antihypertensive drugs may directly block KRAS signaling resulting in improvement in patient outcome or, through a reversion to a KRAS wild-type phenotype, improve the response to anti-EGFR treatment. Antihypertensive angiotensin II receptor blockers are therefore worth further investigation as potential therapeutic candidates in this difficult category of advanced colorectal cancers.

Economic evaluations of angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers in type 2 diabetic nephropathy: a systematic review

Background

Structured comparison of pharmacoeconomic analyses for ACEIs and ARBs in patients with type 2 diabetic nephropathy is still lacking. This review aims to systematically review the cost-effectiveness of both ACEIs and ARBs in type 2 diabetic patients with nephropathy.

Methods

A systematic literature search was performed in MEDLINE and EMBASE for the period from November 1, 1999 to Oct 31, 2011. Two reviewers independently assessed the quality of the articles included and extracted data. All cost-effectiveness results were converted to 2011 Euros.

Results

Up to October 2011, 434 articles were identified. After full-text checking and quality assessment, 30 articles were finally included in this review involving 39 study settings. All 6 ACEIs studies were literature-based evaluations which synthesized data from different sources. Other 33 studies were directed at ARBs and were designed based on specific trials. The Markov model was the most common decision analytic method used in the evaluations. From the cost-effectiveness results, 37 out of 39 studies indicated either ACEIs or ARBs were cost-saving comparing with placebo/conventional treatment, such as amlodipine. A lack of evidence was assessed for valid direct comparison of cost-effectiveness between ACEIs and ARBs.

Conclusion

There is a lack of direct comparisons of ACEIs and ARBs in existing economic evaluations. Considering the current evidence, both ACEIs and ARBs are likely cost-saving comparing with conventional therapy, excluding such RAAS inhibitors.

Impact of microalbuminuria on incident stroke: a meta-analysis

BACKGROUND AND PURPOSE

Microalbuminuria, a marker of both kidney disease and endothelial dysfunction, may be associated with global vascular risk, but the nature and magnitude of the link between microalbuminuria and incident stroke has not been clearly defined. The purpose of this study was to assess the consistency and strength of the association of microalbuminuria with risk of stroke in prospective studies using meta-analysis.

METHODS

We conducted a systematic search of electronic databases and bibliographies for studies reporting a multivariate-adjusted estimate, represented as relative risk with 95% CI, of the association between microalbuminuria and stroke risk. Studies were excluded if a majority of study participants had established kidney disease or pre-eclampsia. Estimates were combined using a random-effect model.

RESULTS

We identified 12 studies, with a total of 48 596 participants and 1263 stroke events. Overall, presence of microalbuminuria was associated with greater stroke risk (relative risk, 1.92; 95% CI, 1.61 to 2.28; P < 0.001) after adjustment for established cardiovascular risk factors. There was evidence of significant heterogeneity in the magnitude of the association across studies (P for heterogeneity < 0.001, I² = 68%), which was partially explained by differences in study population, microalbuminuria definition, and different microalbuminuria-related risk among stroke subtypes. However, in stratified analyses, microalbuminuria was associated with increased risk of subsequent stroke in all subgroups (general population, diabetics, those with known stroke).

CONCLUSIONS

Microalbuminuria is strongly and independently associated with incident stroke risk. Future studies should explore whether microalbuminuria is just a risk marker or a modifiable risk factor for stroke.

Endothelial dysfunction and subsequent decline in glomerular filtration rate in hypertensive patients

BACKGROUND

Chronic kidney disease is a risk factor for cardiovascular disease, increasing all-cause mortality. Some evidence suggests that endothelial dysfunction is present in the early stages of renal insufficiency, but no data exist about its possible role in the progression of renal disease. Thus, we prospectively evaluated the effect of endothelial function on estimated glomerular filtration rate (eGFR) in essential hypertension.

METHODS AND RESULTS

We enrolled 500 never-treated uncomplicated hypertensive subjects with serum creatinine < or =1.5 mg/dL. Endothelial function was measured by strain-gauge plethysmography during intra-arterial infusion of acetylcholine and sodium nitroprusside. eGFR was calculated by use of the Chronic Kidney Disease Epidemiology Collaboration equation. The annual rate of decline of eGFR (DeltaeGFR/y) was determined as the difference between the follow-up and baseline eGFR values, with this value divided by the time interval in years. During follow-up (92.3+/-36.2 months), mean DeltaeGFR/y was 1.49+/-1.65 mL . min(-1) . 1.73 m(-)(2), with no significant differences between men and women (1.55+/-1.72 versus 1.43+/-1.58 mL . min(-1) . 1.73 m(-)(2), respectively; P=0.455). This was correlated with acetylcholine-stimulated forearm blood flow (r=-0.256, P<0.0001), creatinine (r=0.141, P=0.001), systolic blood pressure (r=-0.103, P=0.01), and eGFR (r=0.092, P=0.020). In multivariable regression analysis, forearm blood flow and systolic blood pressure remained associated with change in eGFR. On average, eGFR changed by 0.37 mL . min(-1) . 1.73 m(-)(2) for each 100% change in forearm blood flow (P<0.001) and by 0.1 mL . min(-1) . 1.73 m(-)(2) for each difference of 10 mm Hg in systolic blood pressure (P=0.032).

CONCLUSIONS

We demonstrated that acetylcholine-stimulated vasodilation and systolic blood pressure were associated with eGFR loss after adjustment for other cardiovascular risk factors and antihypertensive treatment.

Proteinuria and clinical outcomes in hypertensive patients

This narrative review focuses on outcomes related to proteinuria in hypertension (HT), and also examines the role of current and future therapeutic strategies. Proteinuria is an independent marker of renal and cardiovascular (CV) disease in hypertensive populations, particularly in high-risk groups such as diabetic patients. Effective blood pressure (BP) control and proteinuria management are associated with significant improvements in the risk of key adverse outcomes, although a causative relationship needs careful assessment. Available antihypertensives have varying effects on proteinuria reduction. Drugs affecting the renin system offer antiproteinuric and renoprotective effects that are probably at least partially independent of their BP effects. Economic evaluations of these interventions confirm their cost-saving benefits relative to other antihypertensives, but outcomes-based research is needed in some settings.

Filtering Medline for a clinical discipline: diagnostic test assessment framework

OBJECTIVE

To develop and test a Medline filter that allows clinicians to search for articles within a clinical discipline, rather than searching the entire Medline database.

DESIGN

Diagnostic test assessment framework with development and validation phases.

SETTING

Sample of 4657 articles published in 2006 from 40 journals. Reviews Each article was manually reviewed, and 19.8% contained information relevant to the discipline of nephrology. The performance of 1 155 087 unique renal filters was compared with the manual review.

MAIN OUTCOME MEASURES

Sensitivity, specificity, precision, and accuracy of each filter.

RESULTS

The best renal filters combined two to 14 terms or phrases and included the terms "kidney" with multiple endings (that is, truncation), "renal replacement therapy", "renal dialysis", "kidney function tests", "renal", "nephr" truncated, "glomerul" truncated, and "proteinuria". These filters achieved peak sensitivities of 97.8% and specificities of 98.5%. Performance of filters remained excellent in the validation phase.

CONCLUSIONS

Medline can be filtered for the discipline of nephrology in a reliable manner. Storing these high performance renal filters in PubMed could help clinicians with their everyday searching. Filters can also be developed for other clinical disciplines by using similar methods.

Economic benefits of treating high-risk hypertension with angiotensin II receptor antagonists (blockers)

Hypertension is one of the leading risk factors for cardiovascular disease and represents a major health and economic burden. Most patients with high- or very high-risk hypertension have multiple cardiovascular risk factors with or without accompanying subclinical organ damage or established cardiovascular or renal disease. Patients with severe hypertension or with moderate hypertension and one to two additional risk factors have absolute 10-year risks of cardiovascular disease of 21-30% and 15-20%, respectively. Current European treatment guidelines recommend that antihypertensive therapy be initiated rapidly and aggressively in patients with high-risk hypertension. Most patients require two or more antihypertensive agents to achieve the strict blood pressure target of <130/80 mmHg. This article reviews the existing cost-effectiveness data on the use of angiotensin II receptor antagonists (blockers) [ARBs] in patients with high-risk hypertension. Aggressive ARB treatment of patients in the early (microalbuminuric) stages of diabetic nephropathy has a significant renoprotective effect, delaying the onset of overt (proteinuric) nephropathy. By slowing the progression of these patients to end-stage renal disease, substantial cost savings can be made. There is a paucity of cost-effectiveness data regarding the use of fixed-dose ARB plus thiazide diuretic combination therapies. Longitudinal cost-benefit studies of this attractive and efficacious first-line treatment option are needed.

Left ventricular hypertrophy and clinical outcomes in hypertensive patients

The prevalence of left ventricular hypertrophy (LVH) rises with severity of hypertension (HT), age, and obesity. Its prevalence ranges from 20% in mildly hypertensive patients to almost 100% in those with severe or complicated HT. However, the diagnosis of LVH is not straightforward, and the definitions and criteria used in clinical studies lack consistency. While many factors play a role in the onset and progression of LVH, blood pressure (BP) is recognized as a central factor. Twenty-four-hour BP measurements are more closely related to LVH than conventional BP readings taken in the clinician's office. Increased renin-angiotensin system (RAS) activity also plays an important role in the development of LVH, and various studies show a correlation between plasma renin activity and left ventricular mass (LVM). LVH is a recognized marker of HT-related target organ damage, and a strong and independent risk factor for adverse cardiovascular (CV) outcomes. CV risk increases with increasing LVM, and decreases with regression of LVH in response to antihypertensive treatment. Therefore the detection, prevention, and reversal of LVH are important goals in HT management. Most antihypertensive drugs can attenuate BP and LVH. However, each drug class may induce LVH regression to a different extent and these extents seldom correlate with the degree of BP reduction achieved. Data from the few large comparative studies in this area suggest that certain classes of antihypertensive drugs and/or their combinations are more effective than others. In particular, calcium channel blockers and drugs that target the RAS, such as angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs), appear to have a specific effect on LVH, independent of BP reduction. Guidelines, therefore, have recommended these drug classes for the treatment of hypertensive patients with LVH.

An economic assessment of losartan-based versus atenolol-based therapy in patients with hypertension and left-ventricular hypertrophy: results from the Losartan Intervention For Endpoint reduction (LIFE) study adapted to The Netherlands

BACKGROUND

The Losartan Intervention For Endpoint reduction (LIFE) study was a randomized, doubleblind trial that compared the effects of losartan-based treatment with those of atenolol-based treatment on cardiovascular disease (CVD)-related morbidity and mortality in 9193 patients with hypertension and left-ventricular hypertrophy (LVH). Compared with atenolol, losartan reduced the combined risk for CVD-related morbidity and mortality by 13% (P = 0.021), and reduced the risk for stroke by 25% (P = 0.001), with comparable blood pressure control in both trial arms.

OBJECTIVE

The aim of this study was to analyze the cost-effectiveness of losartan compared with atenolol in the treatment of stroke from the Dutch health care perspective.

METHODS

Utilization of losartan and atenolol within the trial period (mean, 4.8 years) and an estimation of direct medical costs of stroke for The Netherlands were combined with estimates of reduction in life expectancy through stroke. Medication costs and stroke incidence during 5.5 years of patient follow-up were estimated separately, adjusted for the baseline degree of LVH and Framingham risk score. To estimate lifetime stroke costs, the cumulative incidence of stroke was multiplied by the lifetime direct medical costs attributable to stroke. All costs are in 2006 Dutch prices and discounted following the former (4% costs and effects) and new Dutch guideline (4% costs, 1.5% effects) for conducting pharmacoeconomic analyses.

RESULTS

With 4% discounting, prevention of stroke was associated with a gain of 3.7 life-years. As a consequence, losartan treatment was associated with 0.059 life-year gained (LYG) per patient treated with losartan. Losartan reduced stroke-related costs by 1,076 Euros (US $1,349) per patient. After inclusion of study medication cost, net cost per patient was 51 Euros ($64) higher for losartan than atenolol. The net cost per LYG was 864 Euros ($1083), which is below the Dutch pharmacoeconomic threshold of 20,000 Euros/LYG (~$25,000/LYG) for accepting interventions. The corresponding probability of a cost-effectiveness ratio below this Dutch threshold was 0.95. Discounting money and health following the new Dutch guideline resulted in an even more favorable cost-effectiveness for losartan.

CONCLUSIONS

Results from the present analysis suggest that, in The Netherlands, treatment with losartan compared with atenolol may well be a cost-effective intervention based on the reduced risk for stroke observed in the LIFE trial.