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The corporate bias and the molding of prescription practices: the case of hypertension

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      Drug management of hypertension has been a noticeable example of the influence of the pharmaceutical industry on prescription practices. The worldwide leading brands of blood pressure-lowering agents are angiotensin receptor-blocking agents, although they are considered to be simply substitutes of angiotensin-converting enzyme (ACE) inhibitors. Commercial strategies have been based on the results of clinical trials sponsored by drug companies. Most of them presented distortions in their planning, presentation or interpretation that favored the drugs from the sponsor, i.e., corporate bias. Atenolol, an ineffective blood pressure agent in elderly individuals, was the comparator drug in several trials. In a re-analysis of the INSIGHT trial, deaths appeared to have been counted twice. The LIFE trial appears in the title of more than 120 reproductions of the main and flawed trial, as a massive strategy of scientific marketing. Most guidelines have incorporated the corporate bias from the original studies, and the evidence from better designed studies, such as the ALLHAT trial, have been largely ignored. In trials published recently corporate influences have touched on ethical limits. In the ADVANCE trial, elderly patients with type 2 diabetes and cardiovascular disease or risk factors, allocated to placebo, were not allowed to use diuretic and full doses of an ACE inhibitor, despite the sound evidence of benefit demonstrated in previous trials. As a consequence, they had a 14% higher mortality rate than the participants allocated to the active treatment arm. This reality should be modified immediately, and a greater independence of the academy from the pharmaceutical industry is necessary.

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      Most cited references 33

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      Effects of different blood-pressure-lowering regimens on major cardiovascular events: results of prospectively-designed overviews of randomised trials.

       ,  Fiona Turnbull (2003)
      The benefits of reducing blood pressure on the risks of major cardiovascular disease are well established, but uncertainty remains about the comparative effects of different blood-pressure-lowering regimens. We aimed to estimate effects of strategies based on different drug classes (angiotensin-converting-enzyme [ACE] inhibitors, calcium antagonists, angiotensin-receptor blockers [ARBs], and diuretics or beta blockers) or those targeting different blood pressure goals, on the risks of major cardiovascular events and death. We did seven sets of prospectively-designed overviews with data from 29 randomised trials (n=162341). The trial eligibility criteria, primary outcomes, and main hypotheses were specified before the result of any contributing trial was known. In placebo-controlled trials the relative risks of total major cardiovascular events were reduced by regimens based on ACE inhibitors (22%; 95% CI 17-27) or calcium antagonists (18%; 5-29). Greater risk reductions were produced by regimens that targeted lower blood pressure goals (15%; 5-24). ARB-based regimens reduced the risks of total major cardiovascular events (10%; 4-17) compared with control regimens. There were no significant differences in total major cardiovascular events between regimens based on ACE inhibitors, calcium antagonists, or diuretics or beta blockers, although ACE-inhibitor-based regimens reduced blood pressure less. There was evidence of some differences between active regimens in their effects on cause-specific outcomes. For every outcome other than heart failure, the difference between randomised groups in achieved blood pressure reduction was directly related to the observed difference in risk. Treatment with any commonly-used regimen reduces the risk of total major cardiovascular events, and larger reductions in blood pressure produce larger reductions in risk.
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        Effects of ramipril on cardiovascular and microvascular outcomes in people with diabetes mellitus: results of the HOPE study and MICRO-HOPE substudy. Heart Outcomes Prevention Evaluation Study Investigators.

        Diabetes mellitus is a strong risk factor for cardiovascular and renal disease. We investigated whether the angiotensin-converting-enzyme (ACE) inhibitor ramipril can lower these risks in patients with diabetes. 3577 people with diabetes included in the Heart Outcomes Prevention Evaluation study, aged 55 years or older, who had a previous cardiovascular event or at least one other cardiovascular risk factor, no clinical proteinuria, heart failure, or low ejection fraction, and who were not taking ACE inhibitors, were randomly assigned ramipril (10 mg/day) or placebo, and vitamin E or placebo, according to a two-by-two factorial design. The combined primary outcome was myocardial infarction, stroke, or cardiovascular death. Overt nephropathy was a main outcome in a substudy. The study was stopped 6 months early (after 4.5 years) by the independent data safety and monitoring board because of a consistent benefit of ramipril compared with placebo. Ramipril lowered the risk of the combined primary outcome by 25% (95% CI 12-36, p=0.0004), myocardial infarction by 22% (6-36), stroke by 33% (10-50), cardiovascular death by 37% (21-51), total mortality by 24% (8-37), revascularisation by 17% (2-30), and overt nephropathy by 24% (3-40, p=0.027). After adjustment for the changes in systolic (2.4 mm Hg) and diastolic (1.0 mm Hg) blood pressures, ramipril still lowered the risk of the combined primary outcome by 25% (12-36, p=0.0004). Ramipril was beneficial for cardiovascular events and overt nephropathy in people with diabetes. The cardiovascular benefit was greater than that attributable to the decrease in blood pressure. This treatment represents a vasculoprotective and renoprotective effect for people with diabetes.
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          Postpublication criticism and the shaping of clinical knowledge.

          Letters to the editor are an important means for ensuring accountability of authors and editors. They form a part of the postpublication peer review process. I studied the critical footprint made in the medical literature by 3 randomized trials (Hypertension Optimal Treatment [HOT], Captopril Prevention Project [CAPPP], and Swedish Trial in Old Patients with Hypertension 2 [STOP-2]) published in The Lancet and investigated the extent to which that footprint was preserved in shaping clinical knowledge. Qualitative appraisal of the criticism of each trial, taken from published letters. Agreed weaknesses and unanswered criticisms were identified from the authors' reply. I searched MEDLINE for practice guidelines published after the trial report and sought evidence for incorporation of criticism into these guidelines. From the time of publication to October 2000, HOT was cited in 9 of 36 practice guidelines; CAPPP, in 6 of 36; and STOP-2, not at all. HOT received 14 published criticisms, 5 comments, and 3 questions, of which 15 were responded to. Only 1 criticism, lack of power, was referred to in 1 guideline. CAPPP received 14 criticisms, 9 comments, and 3 questions, of which 8 were responded to. Only 1 criticism, imbalances between groups, was referred to in 1 guideline. STOP-2 received 12 criticisms, 9 comments, and 3 questions, of which only 6 were responded to. More than half of all criticism made in correspondence went unanswered by authors. Important weaknesses in trials were ignored in subsequently published practice guidelines. Failure to recognize the critical footprint of primary research weakens the validity of guidelines and distorts clinical knowledge.

            Author and article information

            [1 ] Universidade Federal do Rio Grande do Sul Brazil
            Role: ND
            Brazilian Journal of Medical and Biological Research
            Braz J Med Biol Res
            Associação Brasileira de Divulgação Científica (Ribeirão Preto )
            March 2009
            : 42
            : 3
            : 224-228


            Product Information: SciELO Brazil


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