Diuretics are preferred first-line over CCBs to optimize reduction of cardiovascular events .
The review does not distinguish between CCBs , ACE inhibitors or ARBs , but does provide evidence supporting the use of CCBs over beta-blockers .
BACKGROUND Calcium channel blockers ( CCBs ) are a relatively new antihypertensive class .
The effect of first-line CCBs on the prevention of cardiovascular events , as compared with other antihypertensive drug classes , is unknown .
OBJECTIVES To determine whether CCBs used as first-line therapy for hypertension are different from other first-line drug classes in reducing the incidence of major adverse cardiovascular events .
Cardiovascular Outcomes in the Irbesartan Diabetic Nephropathy Trial of Patients with Type 2 Diabetes and Overt Nephropathy
Context Previously published results of this r and omized , double-blind trial showed that high-risk patients with type 2 diabetic nephropathy had better renal protection if they were treated with irbesartan rather than amlodipine in addition to conventional antihypertensive therapy . Contribution These detailed analyses showed no differences in overall cardiovascular outcomes between patients given irbesartan or amlodipine .  Fewer patients given irbesartan had heart failure and fewer patients given amlodipine had heart attacks . Caution s The trial had limited power to detect important differences between groups in mortality or strokes , and most patients received several antihypertensive agents . The Editors Patients with diabetes have an increased risk for cardiovascular complications and death ( 1 ) . Studies that analyzed the effects of inhibition of the reninangiotensin system on the risk for cardiovascular complications included a substantial number of patients with diabetes ( 2 - 5 ) or were done exclusively in patients with diabetes ( 6 - 8 ) . The meta- analysis of these studies ( 9 ) , the analysis of the diabetic cohorts in the Heart Outcomes Prevention Evaluation ( HOPE ) study ( 2 ) , and the Losartan Intervention for Endpoint Reduction in Hypertension ( LIFE ) trial ( 5 ) demonstrated that angiotensin-converting enzyme ( ACE ) inhibitors ( 2 , 9 ) and angiotensin-receptor blockers ( 5 ) had a statistically significant advantage over placebo or alternative agents in decreasing the risk for several cardiovascular events . These studies r and omly assigned few patients with renal involvement and overt proteinuria . Overt proteinuria occurred in fewer than 20 % of the 470 patients in the Appropriate Blood Pressure Control in Diabetes ( ABCD ) trial ( 6 ) , and only 11 % of the 1195 patients in the LIFE trial ( 5 ) . The Captopril Prevention Project ( CAPP ) ( 3 ) and the Swedish Trial in Old Patients with Hypertension-2 ( STOP Hypertension-2 ) ( 4 ) did not state the number of patients with diabetes and overt proteinuria . There were no such patients in the Fosinopril versus Amlodipine Cardiovascular Events Trial ( FACET ) ( 7 ) , and patients with dipstick-positive albuminuria were excluded from the HOPE trial ( 2 ) . Since proteinuria is an independent risk factor for cardiovascular disease ( 10 , 11 ) , the data obtained in the aforementioned trials can not be extrapolated to patients with type 2 diabetes and overt nephropathy . Trials performed in such patients have reported a blood pressureindependent effect of two different angiotensin-receptor blocker agents to protect against nephropathy ( 12 , 13 ) without a change in all-cause mortality . Apart from studies in heart failure , few cardiovascular data exist for receptor blockers compared with either placebo or calcium-channel blockers . We report on the analysis of the cardiovascular end points that were monitored as secondary end points in the Irbesartan Diabetic Nephropathy Trial ( IDNT ) ( 12 ) and assess whether an angiotensin II receptor blocker or a calcium-channel blocker alters the risk for cardiovascular events beyond those observed by blood pressure reduction alone without such agents . Methods Patients The IDNT was a r and omized , double-blind study on the effect of treatment with irbesartan or amlodipine compared with placebo in patients with type 2 diabetic nephropathy . The protocol of this study has been published ( 12 , 14 ) . Entry criteria required that patients be between 30 and 70 years of age and have type 2 diabetes mellitus and overt nephropathy , as evidence d by current treatment for hypertension or by a protein excretion rate of 900 mg/d or greater , serum creatinine level of 89 mol/L ( 1.0 mg/dL ) to 266 mol/L ( 3.0 mg/dL ) in women or of 106 mol/L ( 1.2 mg/dL ) to 266 mol/L ( 3.0 mg/dL ) in men , and baseline seated blood pressure greater than 135/85 mm Hg . The institutional review boards of each center approved the protocol . All patients gave written informed consent . Treatment and R and omization Patients were r and omly assigned central ly by computer to receive treatment with irbesartan , 300 mg/d ( Avapro , Bristol-Myers Squibb , Princeton , New Jersey ) ; amlodipine , 10 mg/d ( Norvasc , Pfizer , New York ) ; or matched placebo . To minimize any center effect , r and omization was blocked by center . All patients had blood pressure controlled to the same blood pressure goal of less than 135/85 mm Hg by using antihypertensive agents other than ACE inhibitors , angiotensin II receptor blocking agents , or calcium-channel blockers . For the analysis of cardiovascular end points , patients were followed to initiation of treatment for end-stage renal failure ( dialysis or renal transplantation ) , reaching a serum creatinine level of 530.4 mol/L ( 6.0 mg/dL ) or higher , death , or administrative censoring in December 2000 . Outcomes We prospect ively established cardiovascular outcomes , defined in the Appendix Table . Appendix Table . Classification for Fatal and Nonfatal Cardiovascular Events Ascertainment of Cardiovascular Events Information about hospitalizations and adverse events were screened at Bristol-Myers Squibb , Princeton , New Jersey , by trained , blinded clinical research associates to identify potential cardiovascular events . Investigators used study forms to report and characterize all cardiovascular outcomes . For all potential events , records , including laboratory values , electrocardiograms , and radiographic reports were obtained for clarification . Since myocardial infa rct ions may go unrecognized , a central electrocardiogram reading center was established at Brigham and Women 's Hospital , Boston , Massachusetts , where two cardiologists review ed every electrocardiogram . Electrocardiography was performed at baseline , 6 months , 12 months , and annually thereafter . A total of 5698 electrocardiograms were review ed at the center . When a new Q-wave infa rct ion was found , the cardiologists asked whether a clinical myocardial infa rct ion was reported . Even when myocardial infa rct ions were not clinical ly reported , these Q-wave infa rct ions were adjudicated as myocardial infa rct ions . Adjudication of Cardiovascular Events Investigators at each center reported cardiovascular events , defined in the Appendix Table . The information on all potential events was referred to one member of the Outcomes Confirmation and Classification Committee ( Appendix ) . If the committee member agreed with the judgment of the center investigator , their combined judgment was accepted . If the center investigator and the committee member differed , the case material was review ed by the membership of the committee , whose decision was accepted . Deaths were adjudicated by a Mortality Committee ( Appendix ) . Each death was review ed by two members of the committee and presented to the membership , whose decision was accepted as final . Statistical Analysis For graphical presentation ( Figure ) and overall testing for statistically significant differences among the three treatment groups , time to the first occurrence of either a specific cardiovascular outcome or one of the composite outcomes was analyzed by product-limit survival curves and the log-rank test ( 15 ) . We used proportional hazards modeling to determine hazard ratios . For the cardiovascular death outcome , which could occur only once , we used the st and ard proportional hazards model ( 16 ) , with treatment assignment as the only independent covariate . For other cardiovascular outcomes , which could occur more than once , we used the And ersonGill formulation of the proportional hazards model ( 17 ) , in which patients are considered at risk for the first event from r and omization to the first event , at risk for the second event from the day following the first event to the second event , and so forth , permitting use of all the data . In accordance with the method of Lee and colleagues ( 18 ) , we used a robust variance estimate that accounts for the possibility of correlation of risk for several events within a patient . We believed that occurrence of a first event of a given type increases the likelihood of a subsequent similar event . Therefore , both treatment assignment and a time-dependent covariate indicating whether the event was the first of its type or a subsequent event were included in these analyses . The time-dependent covariate was statistically significant in each case , confirming the above assumption . There was no statistically significant interaction between treatment and the time-dependent covariatethe effects of treatment assignment were similar for first and subsequent events and inclusion of the time-dependent covariate did not change either the estimates of the treatment effect or their statistical significance s. Figure . Time to first cardiovascular composite event as a function of treatment assignment . P Data management and computations were done by using SAS software for Windows , version 8 ( SAS Institute , Inc. , Cary , North Carolina ) , or S-Plus for Windows , version 6.0 ( Insightful Corp. , Seattle , Washington ) . Statistical tests were two sided . A P value of 0.05 or less , unadjusted for the multiple comparisons , was considered statistically significant . Role of the Funding Sources The funding sources were involved in the data collection but not in the analysis or interpretation or the decision to su bmi t the manuscript for publication . Results The baseline characteristics of the three groups are shown in Table 1 . A flow diagram of the study is shown in the Appendix Figure . Table 1 . Baseline Characteristics Appendix Figure . Flow diagram for the Irbesartan Diabetic Nephropathy Trial . Clinical Management During the study , the blood pressure decreased from the baseline values to 140/77 mm Hg in the irbesartan group , 141/77 mm Hg in the amlodipine group , and 144/80 mm Hg in the placebo group . Blood pressure in the two active treatment groups did not differ ; values in both groups were statistically significantly lower than in the placebo group ( P = 0.001 ) . The distribution of non study drugs used to achieve the target blood pressure was similar
Diuretics are preferred first-line over CCBs to optimize reduction of cardiovascular events .
The review does not distinguish between CCBs , ACE inhibitors or ARBs , but does provide evidence supporting the use of CCBs over beta-blockers .
BACKGROUND Calcium channel blockers ( CCBs ) are a relatively new antihypertensive class .
The effect of first-line CCBs on the prevention of cardiovascular events , as compared with other antihypertensive drug classes , is unknown .
OBJECTIVES To determine whether CCBs used as first-line therapy for hypertension are different from other first-line drug classes in reducing the incidence of major adverse cardiovascular events .