The control of hypertension in the. Reaching for Aggressive Blood Pressure Goals: Role of Angiotensin Receptor Blockade in Combination Therapy REPORTS

Transcription

1 REPORTS Reaching for Aggressive Blood Pressure Goals: Role of Angiotensin Receptor Blockade in Combination Therapy By Richard V. Milani, MD Abstract Elevated blood pressure, particularly systolic blood pressure, increases the risk of cardiovascular and renal complications in patients with diabetes. Current national guidelines set the blood pressure goal for those with diabetes at <13/8 mm Hg, which is lower than the goal for the general population (<14/9 mm Hg). Achieving this goal, however, remains difficult, with blood pressure control rates being lower for patients with diabetes than for those without diabetes. Large clinical trials have demonstrated that in most cases, patients will require 2 or more antihypertensive agents to achieve goal blood pressure. The renin-angiotensinaldosterone system plays a key role in regulation of blood pressure. The angiotensin AT 1 receptor blockers (ARBs), which block the effects of angiotensin II, not only lower blood pressure but also provide target-organ protection. These agents are generally well-tolerated, with a side effect profile similar to placebo. Clinical comparisons of different drugs within the class have shown that olmesartan, the newest ARB, produced greater reductions in blood pressure than other agents and that a greater percentage of patients treated with olmesartan reached target blood pressure. Combining an ARB with a diuretic may allow more patients to reach goal blood pressure. (Am J Manag Care. 25;11:S22-S227) The control of hypertension in the United States remains suboptimal despite a high degree of awareness of the disease. The most recent analysis of the National Health and Nutrition Examination Survey (NHANES) in indicated that hypertension was present in 28.7% of the population and that 69.8% of those with hypertension were aware of their diagnosis. 1 Treatment, however, was initiated in only 58.4% of patients with hypertension. Among those with hypertension and those actually receiving treatment, control rates were only 31% and 53.1%, respectively, with control being defined as blood pressure <14/9 mm Hg. The prevalence of hypertension is high in patients with diabetes, and little progress has been made in controlling blood pressure in this high-risk population. The proportion of patients with diabetes with blood pressure at levels recommended by the American Diabetes Association systolic blood pressure (SBP) <13 mm Hg and diastolic blood pressure (DBP) <8 mm Hg did not change significantly between NHANES III conducted in and NHANES (29.% and 35.8%, respectively). 2 Even specialized hypertension clinics have difficulty achieving blood pressure targets in patients with diabetes. Overall, among all hypertensive patients examined at the Rush University Hypertension Service between 1998 and 2, only 259 (59%) of 432 reached the Health Employer Data Information Set (HEDIS) 2 criteria for blood pressure control after 1 year of treatment. 3 Among patients with diabetes, rates of blood pressure goal achievement were even lower, with only 52% achieving a blood pressure of <14/9 mm Hg and fewer reaching more stringent goals (Figures 1 and 2). The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7) 4 established <14/9 mm Hg as the goal blood pressure for patients with hypertension, except those with diabetes and chronic kidney disease, in whom the goal is <13/8 mm Hg. SBP contributes more to cardiovascular disease (CVD) risk than does DBP, particularly in persons older than 5 years. 5 In the Framingham Heart Study, the risks of CVD, heart failure, and peripheral vascular dis- S22 THE AMERICAN JOURNAL OF MANAGED CARE SEPTEMBER 25

2 Reaching for Aggressive Blood Pressure Goals ease were 2 to 6 times greater in subjects with isolated systolic hypertension than in those with an isolated DBP elevation. Similar findings have been observed in the Multiple Risk Factor Intervention Trial (MRFIT). 6 The risk of cardiovascular mortality for patients with SBP of 14 to 16 mm Hg was 81% greater than that of patients with SBP values 14 mm Hg; those with SBP >16 mm Hg had a 94% greater risk of CVD after adjusting for age, associated risk factors, and DBP. When adjusting for SBP levels, CVD and coronary heart disease risk were not associated with changes in DBP. 7 Examination of the database from the Irbesartan Diabetic Nephropathy Trial (IDNT) shows the same large contribution of SBP to renal outcomes. 8 The relationship between blood pressure and cardiovascular events is continuous, and the cost of not achieving goal blood pressure is high in terms of adverse clinical events. Although blood pressure goals may seem aggressive, the risk of CVD actually starts at a blood pressure of 115/75 mm Hg. Lewington and colleagues 9 found that ischemic heart disease mortality increased linearly at all ages starting at SBP >115 mm Hg and DBP >75 mm Hg. In individuals aged 4 to 69 years, ischemic heart disease mortality doubled with every 2-mm Hg increase in SBP and every 1-mm Hg increase in DBP. In a 14-year follow-up analysis of 6859 participants in the Framingham Heart Study, Vasan et al demonstrated a continuous gradient of increasing cardiovascular risk across blood pressure categories that were classified in JNC VI as high normal (13-139/85-89 mm Hg), normal (12-129/8-84 mm Hg), and optimal (<12/8 mm Hg). 1 Therefore, getting patients to their goal blood pressure with some urgency should be the objective in treating patients with hypertension. Inadequacy of Monotherapy Because hypertension is a multifactorial disease, in the vast majority of cases, achieving goal blood pressure will require the use of at least 2 antihypertensive drugs. Figure 1. BP Control According to HEDIS 2 and 21 Criteria in Overall Study Population % at HEDIS goal SBP at goal DBP at goal Materson and colleagues 11 found that monotherapy with any antihypertensive drug class was inadequate to achieve a DBP <95 mm Hg after 1 year of treatment in 4% to 6% of patients with hypertension. In the Hypertension Optimal Treatment HEDIS 2 <14/9 mm Hg HEDIS 21 14/9 mm Hg Both at goal BP indicates blood pressure; HEDIS, Health Employer Data Information Set; SBP, systolic blood pressure; DBP, diastolic blood pressure. Reproduced, with permission, from Singer GM, et al. 3 Figure 2. BP Control in Patients With Diabetes According to HEDIS, JNC VI, and ADA/NKF Criteria % at goal HEDIS 2 <14/9 mm Hg SBP at goal JNC VI <13/85 mm Hg DBP at goal ADA/NKF <13/8 mm Hg Both at goal BP indicates blood pressure; HEDIS, Health Employer Data Information Set; JNC VI, Sixth Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure; ADA/NKF, American Diabetes Association/National Kidney Foundation; SBP, systolic blood pressure; DBP, diastolic blood pressure. Reproduced, with permission, from Singer GM, et al VOL. 11, NO. 7, SUP. THE AMERICAN JOURNAL OF MANAGED CARE S221

3 REPORTS (HOT) study, patients were randomly assigned to 3 different DBP targets ( 9, 85, or 8 mm Hg) with a felodipine-based regimen of antihypertensive agents. Baseline blood pressure was a mean of 161/98 mm Hg in the 6 subjects who were receiving treatment at baseline, and approximately 4% were receiving more than 1 antihypertensive drug. At 5 years, combination therapy was required to achieve goal DBP in up to three fourths of participants, depending on the goal to which they were randomized. Only about one fourth of patients randomized to a goal DBP 8 mm Hg were receiving monotherapy at the end of the study. In the Controlled Onset Verapamil Investigation of Cardiovascular End Points (CONVINCE), 13 68% of the study participants achieved a goal SBP of <14 mm Hg at 3 years. Single-drug therapy was used in only 24% of the study population; 44% were taking 2 drugs, and the remaining 32% were taking 3 or more drugs by the end of the study. Data from the Antihypertensive and Lipid- Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) 14 show a similar pattern. Twenty-seven percent of ALLHAT participants had a baseline blood pressure <14/9 mm Hg; by 5 years, this proportion increased to 66% with use of a mean of 1.6 drugs per patient. As expected, SBP goal was much more difficult to achieve than DBP goal. Bakris and colleagues examined the number of antihypertensive drugs needed to Figure 3. Average Number of Antihypertensive Agents Needed to Achieve BP Goals United Kingdom Prospective Diabetes Study (<85 mm Hg [diastolic BP]) Appropriate Blood Pressure Control in Diabetes Trial (<75 mm Hg [diastolic BP]) Modification of Diet in Renal Disease Study (<92 mm Hg [mean arterial pressure]) Hypertension Optimal Treatment Study (<8 mm Hg [diastolic BP]) African American Study of Kidney Disease (<92 mm Hg [mean arterial pressure]) BP indicates blood pressure. Reproduced, with permission, from Bakris GL, et al Number of antihypertensive agents reach target across several studies in patients with renal disease or diabetes. 15 In the trials examined, patients usually required 3 or 4 drugs to reach target blood pressure (Figure 3). Strategies to Achieve Goal Blood Pressure The renin-angiotensin-aldosterone system (RAAS) plays a central role in the physiology and pathophysiology of the cardiovascular system. Most of the effects of the RAAS are mediated by angiotensin II, a potent vasoconstrictor that acts directly on blood vessels to control peripheral vascular resistance. Angiotensin II also has indirect pressor effects that are mediated by activation of the sympathetic nervous system and by controlling the secretion of aldosterone (and hence salt and water homeostasis). Angiotensin II also acts as a growth factor and is involved in remodeling processes in the heart and blood vessels. Angiotensin AT 1 receptor blockers (ARBs), which block the effects of angiotensin II at the receptor level, are effective antihypertensive agents, as demonstrated in numerous clinical trials. They exhibit dose-dependent efficacy with tolerability comparable with that of placebo, and the rate of persistence with ARBs is greater than that with agents from other antihypertensive classes An analysis of the literature performed by Oparil 19 found that ARB monotherapy generally results in attainment of DBP <9 mm Hg in about 5% of hypertensive patients. At starting doses, reductions in sitting cuff SBP from baseline were 8.4 to 11.3 mm Hg, depending on the ARB, and reductions in sitting cuff DBP were 7.9 to 11.5 mm Hg (Figure 4). One of the recommendations in JNC 7 is to initiate combination therapy as first-line treatment in patients with stage 2 hypertension, defined as a blood pressure of 16/1 mm Hg. Coadministration of 2 agents with differing mechanisms increases the antihypertensive effects of both agents. Adding a diuretic to an ARB markedly and dose-dependently increases the blood pressure lowering effect of the ARB. In a metaanalysis of 43 published randomized controlled trials, 2 hydrochlorothiazide added to S222 THE AMERICAN JOURNAL OF MANAGED CARE SEPTEMBER 25

4 Reaching for Aggressive Blood Pressure Goals Figure 4. Comparison of Starting Dose ARBs: Mean Change in Cuff DBP and SBP at Week 8 OLM 2 mg/day LOS 5 mg/day (n = 146) VAL 8 mg/day (n = 142) IRB 15 mg/day OLM 2 mg/day LOS 5 mg/day (n = 146) VAL 8 mg/day (n = 142) IRB 15 mg/day Mean change in BP (mm Hg) * -8.2 P <.1 SeDBP * -7.9 P <.1 * * -9.9 P < P <.118 SeSBP -8.4 P < P <.425 *Significant vs olmesartan medoxomil. Nonsignificant vs olmesartan medoxomil. Mean baseline BP equals /14 mm Hg. ARBs indicates angiotensin II receptor blockers; DBP, diastolic blood pressure; BP, blood pressure; SBP, systolic blood pressure; SeDBP, seated diastolic blood pressure; SeSBP, seated systolic blood pressure; OLM, olmesartan medoxomil; LOS, losartan potassium; VAL, valsartan; IRB, irbesartan. Adapted, with permission, from Oparil S, et al. Am J Hypertens. 25;18: various ARBs reduced SBP by 16.1 to 2.6 mm Hg and DBP by 9.9 to 13.6 mm Hg. In a controlled study of olmesartan/hydrochlorothiazide in hypertensive patients, the 4-mg/12.5-mg dose produced a significant (P <.1) 19/18-mm Hg reduction from baseline blood pressure, and the 4-mg/25-mg dose demonstrated a significant (P <.1) 27/22-mm Hg reduction from baseline. 21 ARBs and Target-organ Protection Outcomes data demonstrate cardiovascular and end-organ protection with the use of ARBs, providing clinical rationale for their use in the treatment of hypertension. The Irbesartan in Patients with Type 2 Diabetes and Microalbuminuria Study (IRMA 2) is a defining study that demonstrated the impact of an ARB (irbesartan) on proteinuria with appropriate dosing. 22 IRMA 2 examined patients with hypertension, type 2 diabetes, and microalbuminuria, defined as an albumin excretion rate of 2 to 2 µg/min, and normal renal function. Patients were randomly assigned to a control group or treatment with irbesartan 15 or 3 mg/day. The risk of achieving the primary end point progression to clinical proteinuria was reduced by 7% in the group randomized to 3 mg/day of irbesartan compared with placebo. Achievement of normoalbuminuria was possible in 34% of patients who received the 3-mg/day dosage of irbesartan (Figure 5). The beneficial effects on renal function appeared to be independent of the effect on blood pressure, because blood pressure reduction was similar in all 3 groups. A substudy of IRMA 2 analyzed albumin excretion rates 1 month after stopping all treatments. 23 The group that received conventional antihypertensive treatment and those that received conventional antihypertensive therapy plus 15 mg/day of irbesartan had urinary albumin excretion rates return to baseline 1 month after cessation of therapy. The patients assigned to irbesartan 3 mg/day maintained a 5% reduction in albumin excretion rate at 1 month, suggesting preservation of kidney tissue at the higher dose. Another study, IDNT was conducted to determine whether the use of an ARB would protect against the progression of nephropathy in patients with hypertension and type VOL. 11, NO. 7, SUP. THE AMERICAN JOURNAL OF MANAGED CARE S223

5 REPORTS Figure 5. Normalization of Urinary Albumin Excretion Rate in Patients Treated With Irbesartan vs Controls Patients (%) P =.6 24 Control (n = 21) 15 mg/day (n = 195) 3 mg/day (n = 194) Irbesartan Parving HH, et al. N Engl J Med. 21;345: diabetes. 8 In this study, patients were randomly assigned to receive irbesartan, amlodipine, or placebo with a target blood pressure of <135/85 mm Hg. The risk of reaching the primary end point (a composite of a doubling of serum creatinine level, development of end-stage renal disease, or death) was significantly lower in the irbesartan group compared with the amlodipine group (P =.6) and placebo group (P =.2), mainly because of a reduction of the progression of renal dysfunction. No difference in the risk of mortality was observed between the groups. This study therefore established the efficacy of irbesartan to prevent the progression of nephropathy in patients with type 2 diabetes. In IDNT, a 48% reduction in the risk of progressing to a renal end point was observed for every 2-mm Hg reduction in SBP, whereas DBP had little impact. The same strong association between SBP and progression of renal disease was confirmed in patients without diabetes. Further analysis revealed that the risk of renal outcomes was influenced more by follow-up SBP than by baseline SBP. 24 Patients who had an achieved mean SBP in the lowest quartile (<132 mm Hg) had one third the risk of a doubling of serum creatinine or progressing to end-stage renal disease compared with patients in the highest quartile of mean 34 achieved SBP (>149 mm Hg). The relationship between the mean follow-up SBP and the risk of a renal end point was linear all the way down to the lowest SBP levels achieved (<121 mm Hg). The Reduction of End Points in NIDDM with the Angiotensin II Antagonist Losartan (RENAAL) study randomized patients with type 2 diabetes and nephropathy to either a losartan-based regimen (5-1 mg once daily) or placebo in addition to conventional antihypertensive therapy. 25 At 3.4 years of follow-up, losartan was associated with a 16% reduction (P =.2) in the primary composite end point of time to doubling of serum creatinine concentration, end-stage renal disease, or death. The benefit exceeded that attributable to reduction in blood pressure. Losartan was also studied in high-risk hypertensive patients in the Losartan Intervention For Endpoint reduction in Hypertension (LIFE) study, 26 which included patients aged 55 to 8 years with essential hypertension and left ventricular hypertrophy. Patients were randomly assigned to regimens beginning with losartan, titrated to 1 mg/day, or atenolol 5 mg/day. Blood pressure reductions were similar in the 2 groups. Losartan was superior at reducing the incidence of the composite primary end point (cardiovascular mortality, stroke, or myocardial infarction) compared with atenolol, the difference being driven by a significant reduction in stroke (relative risk:.87; P =.21) with losartan. The Valsartan Antihypertensive Longterm Use Evaluation (VALUE) 27 was a study of high-risk patients with hypertension, 92% of whom were receiving antihypertensive therapy before entering the study. They were randomized to a regimen starting with either valsartan 8 mg/day or amlodipine 5 mg/day with elective titration to a target blood pressure of <14/9 mm Hg. Despite a clear blood pressure lowering advantage with amlodipine, the incidence of cardiac morbidity and mortality was not significantly different between the 2 treatment groups. Fewer valsartan-treated patients were hospitalized for heart failure. A key finding in VALUE was that a rapid reduction in blood pressure was associated with more favorable cardiovascular and mortality out- S224 THE AMERICAN JOURNAL OF MANAGED CARE SEPTEMBER 25

6 Reaching for Aggressive Blood Pressure Goals comes throughout the course of the entire study. In both LIFE and VALUE, the ARB-based regimens were associated with significant reductions in new-onset diabetes versus their comparators. Relative Blood Pressure Lowering Effects Within the ARB Class The antihypertensive efficacy of different members of the ARB class has been compared in clinical trials. In a multicenter, randomized trial, Elliott and colleagues found that starting titrated doses of valsartan and losartan were similarly effective in reducing seated SBP and DBP. 28 Candesartan was more effective than losartan in reducing trough seated DBP at 8 weeks ( 11. mm Hg with candesartan vs 8.9 mm Hg with losartan) in a multicenter, randomized study with treatment titrated to effect. 29 Responder rates, defined as the percentage of patients with seated DBP <9 mm Hg, were 64% and 54% with candesartan and losartan, respectively. Irbesartan and the angiotensin-converting enzyme inhibitor enalapril each resulted in more than 6% of patients achieving a DBP 9 mm Hg in a 12-week head-to-head comparison. 3 In an 8-week study comparing these 2 agents in elderly ( 65 years) patients with hypertension, 52.9% of irbesartan-treated patients and 54.9% of enalapril-treated patients achieved a seated DBP 9 mm Hg. 31 A secondary analysis of a trial that directly compared starting doses of 4 ARBs used as monotherapy demonstrated that a combined SBP/DBP goal of <14/9 mm Hg could be attained in 32.4% of patients treated with olmesartan medoxomil, 25.9% treated with irbesartan, 16.1% treated with losartan potassium, and 14.5% treated with valsartan. 19 A similar pattern was observed for the more rigorous goal of <13/85 mm Hg goal, with 12.5%, 4.4%, 3.1%, and 9.4% of patients randomized to olmesartan, losartan, valsartan, and irbesartan, respectively, achieving this goal. Stumpe, et al 32 reviewed 3 head-to-head trials in which olmesartan was compared with 4 other ARBs at their recommended maintenance doses. In all 3 studies, olmesartan was significantly more effective than losartan, valsartan, and candesartan at reducing cuff or 24-hour ambulatory blood pressure in patients with essential hypertension. Similarly, a titrated dose comparison of ARBs found that 4.3% of hypertensive patients treated with olmesartan 4 mg/day reached blood pressure control of <14/9 mm Hg at week 8 compared with 28.5% of those treated with valsartan 16 mg/day (P =.16 vs olmesartan), 2.1% treated with losartan 1 mg/day (P <.1 vs olmesartan), and 12.2% receiving placebo (P <.1 vs olmesartan). 33 A similar trend was observed for the more stringent goal of <13/85 mm Hg at week 12. In this same study, olmesartan reduced seated SBP by 15.1 mm Hg from baseline to week 8 compared with 12.8 mm Hg with valsartan (P =.54 vs olmesartan), 11. mm Hg with losartan (P <.1 vs olmesartan), and 6.2 mm Hg with placebo (P <.1 vs olmesartan). With the importance of achieving goal blood pressure in reducing the risk of clinical events described previously, 9,1 more potent antihypertensive ARBs may offer a clinical advantage over their less potent counterparts. Furthermore, clinical studies suggest a positive impact of early blood pressure goal attainment. In a follow-up to the Systolic Hypertension-Europe (Syst- Eur) study, early compared with delayed blood pressure lowering therapy significantly reduced the rates of stroke and all cardiovascular complications. 34 Considering the total follow-up of 4695 randomized patients, immediate compared with delayed antihypertensive treatment reduced the occurrence of stroke and cardiovascular complications by 28%. In VALUE, also, patients who reached goal within a relatively short time also experienced fewer cardiovascular events than those who achieved goal later. 27 In a comparison of olmesartan 2 mg/day, valsartan 8 mg/day, losartan 5 mg/day, and irbesartan 15 mg/day, more patients reached the cuff blood pressure goal of <14/9 mm Hg at week 2 in the olmesartan group (29%) compared with the losartan (13.9%), valsartan (19%; P = not significant [NS]), and irbesartan (18.6%) groups (Figure 6). 35 Furthermore, more patients reached the more stringent cuff VOL. 11, NO. 7, SUP. THE AMERICAN JOURNAL OF MANAGED CARE S225

7 REPORTS Figure 6. Early Onset of Effect: Patients Reaching BP Control (Cuff Measurement) at Week 2* 4 <14/9 mm Hg 2 <13/85 mm Hg Patients (%) P < P < P < P < P < P <.281 OLM 2 mg/day LOS 5 mg/day (n = 146) VAL 8 mg/day (n = 142) IRB 15 mg/day OLM 2 mg/day LOS 5 mg/day (n = 146) VAL 8 mg/day (n = 142) IRB 15 mg/day *Secondary analysis. Significant vs olmesartan medoxomil. Nonsignificant vs olmesartan medoxomil. Mean baseline BP equals /14 mm Hg. BP indicates blood pressure; OLM, olmesartan medoxomil; LOS, losartan potassium; VAL, valsartan; IRB, irbesartan. Data on file, Sankyo Pharma Inc. blood pressure goal of <13/85 mm Hg in the olmesartan group (9.7%) compared with the losartan potassium (2.1%), valsartan (3.5%), and irbesartan (6.2%; P = NS) groups. At week 2, olmesartan was significantly more effective than each of the other 3 ARBs in reducing seated SBP and DBP. Conclusion The risk of cardiovascular events increases linearly with blood pressure. Achieving target blood pressure goals is associated with improved clinical outcomes. In most cases, multiple antihypertensive agents will be required to achieve goal blood pressures, especially in patients with diabetes. The ARBs have demonstrated blood pressure lowering efficacy and offer targetorgan protection. In clinical trials, ARBs have reduced the incidence of adverse renal and cardiovascular outcomes versus comparators, independent of their effect on blood pressure. These agents are generally well-tolerated, with a side effect profile comparable with placebo. The addition of hydrochlorothiazide improves the blood pressure lowering efficacy of ARBs and allows more patients to achieve goal blood pressures. Comparative studies of ARBs show differences in the percentage of patients who achieve goal blood pressures, with olmesartan, the newest ARB, being the most potent. A study of patients >6 years of age with diabetes showed that treatment to a blood pressure goal of <13/85 mm Hg rather than a less stringent goal of <14/9 mm Hg resulted in cost savings over a patient s lifetime. 36 Treatment to the lower goal of <13/8 mm Hg recommended by JNC 7 may prove to be even more cost effective in improving long-term outcomes. REFERENCES 1. Hajjar I, Kotchen TA. Trends in prevalence, awareness, treatment, and control of hypertension in the United States, JAMA. 23;29: Saydah SH, Fradkin J, Cowie CC. Poor control of risk factors for vascular disease among adults with previously diagnosed diabetes. JAMA. 24;291: Singer GM, Izhar M, Black HR. Guidelines for hypertension: are quality-assurance measures on target? Hypertension. 24;43: Chobanian AV, Bakris GL, Black HR, et al. National Heart, Lung, and Blood Institute Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. National High Blood Pressure S226 THE AMERICAN JOURNAL OF MANAGED CARE SEPTEMBER 25

8 Reaching for Aggressive Blood Pressure Goals Education Program Coordinating Committee. The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure: the JNC 7 report. JAMA. 23;289: Stamler J, Neaton JD, Wentworth D. Blood pressure (systolic and diastolic) and the risk of fatal coronary heart disease. Hypertension. 1989;13(suppl 5):I2-I Rutan GH, Kuller LH, Neaton JD, Wentworth DN, McDonald RH, Smith WM. Mortality associated with diastolic hypertension and isolated systolic hypertension among men screened for the Multiple Risk Factor Intervention Trial. Circulation. 1988;77: Deedwania PC. The changing face of hypertension: is systolic blood pressure the final answer? Arch Intern Med. 22;162: Lewis EJ, Hunsicker LG, Clarke WR, et al; for the Collaborative Study Group. Renoprotective effect of the angiotensin-receptor antagonist irbesartan in patients with nephropathy due to type 2 diabetes. N Engl J Med. 21;345: Lewington S, Clarke R, Qizilbash N, Peto R, Collins R; for the Prospective Studies Collaboration. Age-specific relevance of usual blood pressure to vascular mortality: a meta-analysis of individual data for one million adults in 61 prospective studies. Lancet. 22;36: Vasan RS, Larson MG, Leip EP, et al. Impact of highnormal blood pressure on the risk of cardiovascular disease. N Engl J Med. 21;345: Materson BJ, Reda DJ, Cushman WC. Department of Veterans Affairs single-drug therapy of hypertension study. Revised figures and new data. Department of Veterans Affairs Cooperative Study Group on Antihypertensive Agents. Am J Hypertens. 1995;8: Hansson L, Zanchetti A, Carruthers SG, et al. Effects of intensive blood pressure lowering and low-dose aspirin in patients with hypertension: principal results of the Hypertension Optimal Treatment (HOT) randomised trial. The HOT study group. Lancet. 1998;351: Black HR. Elliott WJ, Neaton JD, et al. Baseline characteristics and early blood pressure control in the CONVINCE trial. Hypertension. 21;37: ALLHAT Officers and Coodinators; ALLHAT Collaborative Research Group. The Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial. Major outcomes in high-risk hypertensive patients randomized to angiotensin-converting enzyme inhibitor or calcium channel blocker vs diuretic: the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT). JAMA. 22;288: Bakris GL, Williams M, Dworkin L, et al. Preserving renal function in adults with hypertension and diabetes: a consensus approach. National Kidney Foundation Hypertension and Diabetes Executive Committees Working Group. Am J Kidney Dis. 2;36: Hasford J, Mimran A, Simons WR. A populationbased European cohort study of persistence in newly diagnosed hypertensive patients. J Hum Hypertens. 22;16: Degli Esposti E, Sturani A, Di Martino M, et al. Long-term persistence with antihypertensive drugs in new patients. J Hum Hypertens. 22;16: Marentette MA, Gerth WC, Billings DK, Zarnke KB. Antihypertensive persistence and drug class. Can J Cardiol. 22;18: Oparil S, Silfani TN, Walker JF. Role of angiotensin receptor blockers as monotherapy in reaching blood pressure goals. Am J Hypertens. 25;18: Conlin PR, Spence JD, Williams B, et al. Angiotensin II antagonists for hypertension: are there differences in efficacy? Am J Hypertens. 2;13: Chrysant SG, Weber MA, Wang AC, et al. Evaluation of antihypertensive therapy with the combination of olmesartan medoxomil and hydrochlorothiazide. Am J Hypertens. 24;17: Parving HH, Lehnert H, Bröchner-Mortensen J, et al. The effect of irbesartan on the development of diabetic nephropathy in patients with type 2 diabetes. N Engl J Med. 21;345: Andersen S, Bröchner-Mortensen J, Parving HH. Kidney function during and after withdrawal of long-term irbesartan treatment in patients with type 2 diabetes and microalbuminuria. Diabetes Care. 23;26: Pohl MA. Presented at: American Society of Nephrology 35th annual meeting and scientific exposition; November 1-4, 22; Philadelphia, Pa. Abstract SU-P Brenner BM, Cooper ME, de Zeeuw D, et al; for the RENAAL Study Investigators. Effects of losartan on renal and cardiovascular outcomes in patients with type 2 diabetes and nephropathy. N Engl J Med. 21;345: Dahlof B, Devereux RB, Kjeldsen SE, et al; for the LIFE study group. Cardiovascular morbidity and mortality in the Losartan Intervention For Endpoint reduction in hypertension study (LIFE): a randomised trial against atenolol. Lancet. 22;359: Julius S, Kjeldesen JE, Weber M, et al; for the VALUE trial group. Outcomes in hypertensive patients at high cardiovascular risk treated with regimens based on valsartan or amlodipine: the VALUE trial. Lancet. 24;363: Elliott WJ, Calhoun DA, DeLucca PT, Gazdick LP, Kerns DE, Zeldin RK. Losartan versus valsartan in the treatment of patients with mild to moderate essential hypertension: data from a multicenter, randomized double-blind, 12-week trial. Clin Ther. 21;23: Gradman AH, Lewis A, Bowling BT, et al. Comparison effects of candesartan cilexitil and losartan in patients with essential hypertension. Candesartan Versus Losartan Efficacy Comparison (CANDLE) Study Group. Heart Dis. 1999;1: Mimran A, Ruilope L, Kermin L, et al. A randomised, double-blind comparison of the angiotensin II receptor II antagonist, irbesartan, with the full dose range of enalapril for the treatment of mild-to-moderate hypertension. J Hum Hypertens. 1998;12: Lacourcière Y. A multicenter, randomized doubleblind study of the antihypertensive efficacy and tolerability of irbesartan in patients aged 65 years with mild to moderate hypertension. Clin Ther. 2;22: Stumpe KO. Olmesartan compared with other angiotensin II receptor antagonists: head-to-head trials. Clin Ther. 24;26(suppl A):A33-A Sankyo Pharma. Data on file. 34. Staessen JA, Thijs L, Fagard R, et al; for the Systolic Hypertension in Europe (Syst-Eur) Trial Investigators. Effects of immediate versus delayed antihypertensive therapy on outcome in the Systolic Hypertension in Europe Trial. J Hypertens. 24;22: Sankyo Pharma. Data on file. 36. Elliott WJ, Weir DR, Black HR. Cost-effectiveness of the lower treatment goal (of JNC VI) for diabetic hypertensive patients. Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. Arch Intern Med. 2;16: VOL. 11, NO. 7, SUP. THE AMERICAN JOURNAL OF MANAGED CARE S227