Lancet
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Meta Analysis Comparative Study
Effects of ACE inhibitors, calcium antagonists, and other blood-pressure-lowering drugs: results of prospectively designed overviews of randomised trials. Blood Pressure Lowering Treatment Trialists' Collaboration.
This programme of overviews of randomised trials was established to investigate the effects of angiotensin-converting-enzyme (ACE) inhibitors, calcium antagonists, and other blood-pressure-lowering drugs on mortality and major cardiovascular morbidity in several populations of patients. We did separate overviews of trials comparing active treatment regimens with placebo, trials comparing more intensive and less intensive blood-pressure-lowering strategies, and trials comparing treatment regimens based on different drug classes. ⋯ Strong evidence of benefits of ACE inhibitors and calcium antagonists is provided by the overviews of placebo-controlled trials. There is weaker evidence of differences between treatment regimens of differing intensities and of differences between treatment regimens based on different drug classes. Data from continuing trials of blood-pressure-lowering drugs will substantially increase the evidence available about any real differences that might exist between regimens.
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Despite more than 70 randomised trials, the effect of chemotherapy on non-metastatic head and neck squamous-cell carcinoma remains uncertain. We did three meta-analyses of the impact of survival on chemotherapy added to locoregional treatment. ⋯ Because the main meta-analysis showed only a small significant survival benefit in favour of chemotherapy, the routine use of chemotherapy is debatable. For larynx preservation, the non-significant negative effect of chemotherapy in the organ-preservation strategy indicates that this procedure must remain investigational.
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The original report of a possible association between myocardial infarction and the insertion/deletion (I/D) polymorphism of the gene for the angiotensin-1-converting enzyme (ACE) indicated a risk ratio for myocardial infarction with the DD genotype of 1.34 (95% CI 1.05-1.70), and the association was claimed to be particularly strong in a retrospectively defined low-risk subgroup (3.2 [95% CI 1.7-5.9). Subsequent investigations reached varying conclusions, but all were small, and much larger studies were needed. ⋯ This study involved many more cases than any previously reported study of this question, but did not confirm the existence of any substantial association. In an updated meta-analysis of these results with those of previously published studies, the risk ratio for myocardial infarction with the DD genotype seems to lie in the range 1.0 to about 1.1. Although an increase in risk of up to about 10-15% cannot be ruled out, substantially more extreme risks can be. Moreover, there are not especially strong associations in the subgroups previously selected for emphasis. These findings illustrate the need for some studies of candidate genes to involve much larger populations than is customary, without undue emphasis on retrospectively defined subgroups.
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The debate on breastfeeding in areas of high HIV prevalence has led to the development of simulation models that attempt to assess the risks and benefits associated with breastfeeding. An essential element of these simulations is the extent to which breastfeeding protects against infant and child mortality; however, few studies are available on this topic. We did a pooled analysis of studies that assessed the effect of not breastfeeding on the risk of death due to infectious diseases. ⋯ These results may help shape policy decisions about feeding choices in the face of the HIV epidemic. Of particular relevance is the need to account for declining levels of protection with age in infancy, the continued protection afforded during the second year of life, and the question of the safety of breastmilk substitutes in families of low socioeconomic status.
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Meta Analysis Comparative Study
Pharmacological strategies to decrease excessive blood loss in cardiac surgery: a meta-analysis of clinically relevant endpoints.
Excessive bleeding may complicate cardiac surgery, and is associated with increased morbidity and mortality. Pharmacological strategies to decrease perioperative bleeding have been investigated in a large number of controlled trials, most of which have shown a decrease in blood loss. However, most studies lacked sufficient power to detect a beneficial effect on clinically more relevant outcomes. We did a meta-analysis of all randomised, controlled trials of the three most frequently used pharmacological strategies to decrease perioperative blood loss (aprotinin, lysine analogues [aminocaproic acid and tranexamic acid], and desmopressin). ⋯ Pharmacological strategies that decrease perioperative blood loss in cardiac surgery, in particular aprotinin and lysine analogues, also decrease mortality, the need for rethoracotomy, and the proportion of patients receiving a blood transfusion.