Statistical analysis
VTE
Analysis was conducted in both the per-protocol (PP) and as randomized populations. The per-protocol population excluded patients who did not meet all inclusion and non-inclusion criteria, were not treated using the strategy allocated to the ED, had a missing value for the primary end point, or had any other major protocol deviation identified during the data review just before the database was frozen. In the as randomized population, patients with missing values for the primary endpoint were classified as having a VTE.Baseline patient characteristics were described overall and for each group using the number (percentage) for categorical variables and the mean (SD). The arithmetic mean is the usual summary statistic to consider the total cost from the budgetary perspective.Differences in mean costs and frequency of VTE were estimated using separate generalized linear-regression mixed models, with gamma distribution and log link for costs and a Bernoulli distribution (logit link) for frequency, both of which were estimated controlling for diagnostic strategy, period, strategy-by-period interaction as fixed effects, and cluster at the hospital-level as a random effect. We then calculated incremental cost-effectiveness ratio (ICER) by dividing the incremental costs by the incremental effects. The ICER indicates the cost per undetected VTE averted.The uncertainty surrounding these point estimates was examined using a two-stage non-parametric bootstrapping technique with 1,000 replications [