Similar approaches have been used in mortality comparisons between winners and losers of specific events to identify the effect of winning that event on mortality (for example, comparisons of mortality among actors winning versus losing an Academy Award, baseball players inducted into the Hall of Fame, and Nobel Prize winners).
Using the price of the purchased ticket as a proxy for socioeconomic class, the largest spread of all the mortality comparisons is between the rate among upper- and middle-class children under age 15 (3 percent) and their lower-class comparison group (70 percent).
We consider two different distributions for heterogeneity that pertain to a subjective outcome (the most frequently reported outcome in our data) and all-cause mortality for comparisons between pharmacological interventions and placebo; according to [ 22] these are τ ~ LN -2.13, 1.58) and τ ~ LN -2.13, 1.58) (mediandτ = 0.02 with (IQR 0.01, 0.04)).
These results are in line with the excess mortality rate ratio represented in Figure 2A, which shows an excess mortality rate ratio comparison between the two populations over follow-up that differs little from 1. Figure 2B highlights the impact of having a perfect traceback system from DCI cases in the case where 10% of initial diagnoses are missed.
14 There was no difference in 72 h mortality between comparison groups (RR 0.99, 95% CI 0.49 to 1.98, low quality evidence; see online supplementary tables S4 and S5).
For a more impartial evaluation of surgical timing and its effect on mortality and morbidity, a comparison between patients of equal predicted morbidity and mortality rates at admission and different surgical time points was conducted to exclude confounding factors such as differing physiological compromise and medical comorbidities.
The results of the comparison between mortality-available and mortality-unavailable subgroups (Tables 2 and 3) suggest that there was a higher burden of frailty at baseline in those for whom mortality information could not be obtained at follow-up.
Comparison between mortality estimates reveals some interesting results.
If the risk of not being diagnosed is related to diabetes type, this may affect the comparison between mortality in autoimmune diabetes versus type 2 diabetes.
First, the small number of patients studied and the single-centre design weaken the comparison between mortality and recovery of kidney function, and the exclusion of the sickest patients (17 patients receiving a noradrenaline dose higher than 0.7 μg/kg/min) may have biased the study towards a benefit for EDD.
