Figure 5

Manhattan-like three-dimensional matrix building upon the risks of systematic error, random error, and design error. The evidence with the lowest systematic, random, and design error is represented by the tallest skyscrapers, located on 'the upper west side'. a. Outcomes with benefit of peri-operative beta-blockade versus placebo. b. Outcomes with harm of peri-operative beta-blockade versus placebo. A 'quick guide' to the perception of the figure: If you want to know what the evidence is for peri-operative beta-blockade to influence myocardial infarction: go to the yellow bars and read 1) Level of evidence (the risk of systematic error) and 2) standard error (the risk of random error). Data with risk of systematic error >level 2b and random error SE >1.0 were omitted from the figure. The guidelines, which advocate the use of peri-operative beta-blockade, were not included in this figure since the systematic error is level 5 and the random error cannot be calculated (not based on data) [58]. The SE of outcomes with zero events cannot be calculated either. From these 'benefit' and 'harm' Manhattan figures, one can see at a glance that beta-blockers may provide benefit to patients in terms of nonfatal myocardial infarction (yellow bars). However, one can also see that beta-blockers may cause harm to patients in terms of all-cause mortality (red bars), cardiovascular mortality (blue bars), and nonfatal stroke (green bars). Reading the dimension of systematic error it is immediately clear that there is level 1a evidence available for all these four outcome measures. Reading the dimension of random error on this systematic error level of evidence shows that there is a small risk of random error considering all-cause mortality (0,12), cardiovascular mortality (0,16), and nonfatal myocardial infarction (0,10), and a moderate risk of random error considering nonfatal stroke (0,28). It is clear at a glance that the best available evidence does not support peri-operative beta-blockade for major non-cardiac surgery. SE = 0 to 0,10 = ignorable risk of random error. SE = 0,10 to 0,20 = small risk of random error. SE = 0,20 to 0,30 = moderate risk of random error. SE = 0,30 to 0,50 = substantial risk of random error. SE = >0,50 = high risk of random error. A clean version for creating a Manhattan figure can be obtained at the Copenhagen Trial Unit's homepage (http://ctu.rh.dk).