Meta-analysis studies mortality

Fig. 8.11 Meta-analysis of mortality following coronary bypPass surgery in fhe study reported by Yusuf et ah, 1994.

In a recent meta-analysis study on European men and women (25), high plasma concentrations of a- and /3-carotene were associated both with lower mortality from all causes and cancer, For cardiovascular mortality the inverse association was confined to the elderly with body mass index <25. 

A Cochrane meta-analysis studied the efficacy and safety of mucolytic agents in COPD patients. The meta-analysis included 30 trials and 7436 patients [93 ]. Mucolytics appeared to have a safe profile, without any effect on mortality (OR = 0.75, 95% Cl = 0.35,1.64) or the frequency of adverse effects. 

Over the last decade, several studies in tens of thousands of patients have revealed that lowering cholesterol, specifically lowering LDL cholesterol with statins, is effective for both primary and secondary prevention of IHD-related events. Statins shown to decrease morbidity and mortality associated with IHD include lovastatin, simvastatin, pravastatin, and atorvas-tatin.22,23 A recent meta-analysis showed that the risk of major adverse cardiac events is reduced by 21% with the use of statins in patients at high risk for IHD-related events.23... 

A recent meta-analysis was performed on all published human trials that used low-dose dopamine in the prevention or treatment of ARE20 A total of 61 studies were identified that randomized more than 3300 patients to low-dose dopamine or placebo. Results reveal no significant difference between the treatment and control groups for mortality, requirement for RRT, or adverse effects. 

Animal and human studies support the use of antibiotics for the prevention of infectious morbidity and mortality in severe ANP. The most effective antimicrobial agents are the fluoroquinolones, imipenem-cilastatin, and metronidazole, which achieve adequate penetration into pancreatic juice and necrotic tissue and inhibit the growth of enteric bacteria. Although a recent meta-analysis [185] suggested that prophylactic antibiotic administration reduces sepsis and mortality and this approach has been recommended by recent guidelines and consensus state-... 

Horne R and Weinman J (1999) Patients beliefs about prescribed medicines and their role in adherence to treatment in chronic physical illness. J Psychosom Res 47(6) 555-567 Kannisto V, Lauritsen J, Thatcher AR et al. (1994) Reductions in mortality at advanced age several decades of evidence from 27 countries. Population and development review 20(4) 793-810 Lazarou J, Pomeranz BH, Corey PN (1998) Incidence of adverse drug reactions in hospitalized patients a meta- analysis of prospective studies. JAMA 279(15) 1200-1205 LeSage J (1991) Polypharmacy in geriatric patients. Nurs Clin North Am 26(2) 273-290 Pitkala KH, Strandberg TE, Tilvis RS (2001) Is it possible to reduce polypharmacy in the elderly ... 

Meta-analysis is a method often used to determine the effectiveness of a drug but to date it has rarely been used to assess safety. One case illustrates how this technique can help. Six studies examining the use of intravenous lidocaine for acute myocardial infarction did not, on an individual basis, give strong enough evidence to support the hypothesis that this technique could cause excess mortality. The meta-analysis, however, was able to demonstrate this. ... 

He, K., Song, Y., Daviglus, M. L., Liu, K., Van Horn, L., Dyer, A. R., and Greenland, P. (2004). Accumulated evidence on fish consumption and coronary heart disease mortality. A meta-analysis of cohort studies. Circulation 109,2705-2711. 

Huxley RR, Neil HAW. 2003. The relation between dietary flavonol intake and coronary heart disease mortality A meta-analysis of prospective cohort studies. 

The interest in dietary flavonoids has grown in the last 15 years after the publication of the study of Hertog et al. [1993] showing an inverse correlation between dietary consumption of flavonols and flavones and reduced incidence and mortality from ischemic heart disease. Most prospective epidemiological studies carried out have found a similar relationship regarding ischemic heart disease while a possible inverse relationship with stroke is less clear [Hertog et al., 1997 Knekt et al., 1996 Rimm et al., 1996 Yochum et al., 1999 Hirvonen et al., 2001 Arai et al., 2000 Mursu et al., 2008], The meta-analysis... 

There is clear epidemiologic evidence of a continuous (log linear) relation between cholesterol levels and the risk of CHD events and mortality, both within communities and when comparing different populations (3). Although it has been estimated that each I % decrement in total cholesterol is associated with a 2% to 3% decrease in CHD risk, regression dilution bias underestimates the strength of the association. From the meta-analysis of international studies, it has been suggested that each 10% decrement in total cholesterol is associated with 38% reduction in CHD events (4). 

In case LDL oxidation is considered as an important risk factor, the dosage of vitamin E may be important to determine a clinical effect. However, with respect to inhibition of protein kinase-C and the release of proinflammatory cytokines the intracellular transfer of RRRT (natural vitamin E) by the tocopherol-associated protein may be a crucial point. Consequently, natural vitamin E is considered more effective than the synthetic one. Since the activity on LDL oxidation was pointed out as important for the prevention of cardiovascular disease, most of the long-term trials with vitamin E were conducted at dosages >200 mg/day (about 200 lU/d). In a recent meta-analysis the association of plasma levels and mortality was studied in 1168 elderly European men and women (25). No association was found between the plasma concentration and all-cause or cause-specific mortality. 

Another meta-analysis has been conducted on 19 clinical trials with vitamin E supplementation and follow-up of a duration of more than one year. Nine trials were using vitamin E only without any other supplement and six of them were double-blind/placebo-controlled studies (28), The outcome of the analysis was that high dosages (>400 ILJ/d) may increase all-cause mortality and, therefore, should be avoided. Since in many studies other supplements were used concomitantly to vitamin E the authors concluded, the use of any high-dose supplement should be discouraged until evidence of efficacy is documented from appropriately designed clinical trials. ... 

Although the majority of randomized studies revealed only insignificant trends toward benefit in the general population, a meta-analysis of nine such studies performed from 1965 to 1987 (two were double-blinded and seven were open) revealed a significant mortality benefit with an odds ratio (OR) of 0.72 [95% confidence interval (Cl) = 0.57-0.90] (47). In the four most recent trials in the general population to date (48-50), only one presented a significant mortality benefit in the GIK infusion group (51). 

Stieb DM, Judek S, Burnett RT (2002) Meta-analysis of time-series studies of air pollution and mortality Effects of gases and particles and the influence of causes of death, age, and season. J Air Waste Manage Assoc, 52 470-484. 

Danesh J, Whincup P, Walker M et al. (2000). Chlamydia pneumoniae IgG litres and coronary heart disease prospective study and metaanalysis. British Medical Journal 321 208-213 Danesh J, Whincup P, Walker M (2003). Chlamydia pneumoniae IgA litres and coronary heart disease prospective study and meta-analysis. European Heart Journal 24 881 Danesh J, Lewington S, Thompson SG et al. (2005). Plasma fibrinogen level and the risk of major cardiovascular diseases and non-vascular mortality an individual participant meta-analysis. Journal of American Medical Association 294 1799-1809 Diabetes Control and Complications Trial/ Epidemiology of Diabetes Interventions and Complications Research Group (2003). 

In July 1998, The Cochrane Injuries Group Albumin Reviewers published a meta-analysis comparing the use of albumin with the use of crystalloids or no treatment in critically ill patients (12). The review was based on 30 randomized, controlled studies, involving a total of 1419 patients with hypovolemia due to trauma, surgery, burns, or hypoalbuminemia. There was excess mortality in the albumin group of about 6%, and the authors concluded that albumin should not be used outside rigorously conducted randomized controlled trials. The review elicited numerous mostly critical comments. For example, it was commented that a meta-analysis is not exact and that in this specific studythe study had conflated three separate indications that were not comparable (5). 

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