Background: Model replication is important because it enables researchers to check research integrity and transparency and, potentially, to inform the model conceptualization process when developing a new or updated model. Objective:The aim of this study was to evaluate the replicability of published decision analytic models and to identify the barriers and facilitators to replication.Methods: Replication attempts of 5 published economic modeling studies were made. The replications were conducted using only publicly available information within the manuscripts and supplementary materials. The replicator attempted to reproduce the key results detailed in the paper, for example, the total cost, total outcomes, and if applicable, incremental costeffectiveness ratio reported. Although a replication attempt was not explicitly defined as a success or failure, the replicated results were compared for percentage difference to the original results.Results: In conducting the replication attempts, common barriers and facilitators emerged. For most case studies, the replicator needed to make additional assumptions when recreating the model. This was often exacerbated by conflicting information being presented in the text and the tables. Across the case studies, the variation between original and replicated results ranged from 24.54% to 108.00% for costs and 23.81% to 0.40% for outcomes. Conclusion:This study demonstrates that although models may appear to be comprehensively reported, it is often not enough to facilitate a precise replication. Further work is needed to understand how to improve model transparency and in turn increase the chances of replication, thus ensuring future usability.

Background This study aimed to determine the impact of preoperative exposure to intravenous contrast for CT and the risk of developing postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery. Methods This prospective, multicentre cohort study included adults undergoing gastrointestinal resection, stoma reversal or liver resection. Both elective and emergency procedures were included. Preoperative exposure to intravenous contrast was defined as exposure to contrast administered for the purposes of CT up to 7 days before surgery. The primary endpoint was the rate of AKI within 7 days. Propensity score‐matched models were adjusted for patient, disease and operative variables. In a sensitivity analysis, a propensity score‐matched model explored the association between preoperative exposure to contrast and AKI in the first 48 h after surgery. Results A total of 5378 patients were included across 173 centres. Overall, 1249 patients (23·2 per cent) received intravenous contrast. The overall rate of AKI within 7 days of surgery was 13·4 per cent (718 of 5378). In the propensity score‐matched model, preoperative exposure to contrast was not associated with AKI within 7 days (odds ratio (OR) 0·95, 95 per cent c.i. 0·73 to 1·21; P = 0·669). The sensitivity analysis showed no association between preoperative contrast administration and AKI within 48 h after operation (OR 1·09, 0·84 to 1·41; P = 0·498). Conclusion There was no association between preoperative intravenous contrast administered for CT up to 7 days before surgery and postoperative AKI. Risk of contrast‐induced nephropathy should not be used as a reason to avoid contrast‐enhanced CT.

The peri-operative use of angiotensin-converting enzyme inhibitors or angiotensin-2 receptor blockers is thought to be associated with an increased risk of postoperative acute kidney injury. To reduce this risk, these agents are commonly withheld during the peri-operative period. This study aimed to investigate if withholding angiotensin-converting enzyme inhibitors or angiotensin-2 receptor blockers peri-operatively reduces the risk of acute kidney injury following major non-cardiac surgery. Patients undergoing elective major surgery on the gastrointestinal tract and/or the liver were eligible for inclusion in this prospective study. The primary outcome was the development of acute kidney injury within seven days of operation. Adjusted multi-level models were used to account for centre-level effects and propensity score matching was used to reduce the effects of selection bias between treatment groups. A total of 949 patients were included from 160 centres across the UK and Republic of Ireland. From this population, 573 (60.4%) patients had their angiotensin-converting enzyme inhibitors or angiotensin-2 receptor blockers withheld during the peri-operative period. One hundred and seventy-five (18.4%) patients developed acute kidney injury; there was no difference in the incidence of acute kidney injury between patients who had their angiotensin-converting enzyme inhibitors or angiotensin-2 receptor blockers continued or withheld (107 (18.7%) vs. 68 (18.1%), respectively; p = 0.914). Following propensity matching, withholding angiotensin-converting enzyme inhibitors or angiotensin-2 receptor blockers did not demonstrate a protective effect against the development of postoperative acute kidney injury (OR (95%CI) 0.89 (0.58-1.34); p = 0.567).

Radial head fractures are a common fracture involving the elbow joint. Patients typically present after a fall onto an outstretched hand with elbow pain and swelling. Without adequate treatment, this can lead to long-term complications, including loss of elbow motion and pain. Radial head fractures may also be associated with other injuries including elbow dislocation, neighbouring bony fractures and associated ligamentous rupture. It is therefore imperative that hospital clinicians understand the diagnosis and treatment of this condition. The plain radiograph is the optimum method to diagnose a radial head fracture. These fractures can be managed using a variety of techniques, from non-surgical conservative methods for the undisplaced fracture through to surgical fixation, radial head replacement and excision for the more complex, displaced fracture.

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