Evaluation of appendicitis risk prediction models in adults with suspected appendicitis

Background Appendicitis is the most common general surgical emergency worldwide, but its diagnosis remains challenging. The aim of this study was to determine whether existing risk prediction models can reliably identify patients presenting to hospital in the UK with acute right iliac fossa (RIF) pain who are at low risk of appendicitis. Methods A systematic search was completed to identify all existing appendicitis risk prediction models. Models were validated using UK data from an international prospective cohort study that captured consecutive patients aged 16–45 years presenting to hospital with acute RIF in March to June 2017. The main outcome was best achievable model specificity (proportion of patients who did not have appendicitis correctly classified as low risk) whilst maintaining a failure rate below 5 per cent (proportion of patients identified as low risk who actually had appendicitis). Results Some 5345 patients across 154 UK hospitals were identified, of which two‐thirds (3613 of 5345, 67·6 per cent) were women. Women were more than twice as likely to undergo surgery with removal of a histologically normal appendix (272 of 964, 28·2 per cent) than men (120 of 993, 12·1 per cent) (relative risk 2·33, 95 per cent c.i. 1·92 to 2·84; P < 0·001). Of 15 validated risk prediction models, the Adult Appendicitis Score performed best (cut‐off score 8 or less, specificity 63·1 per cent, failure rate 3·7 per cent). The Appendicitis Inflammatory Response Score performed best for men (cut‐off score 2 or less, specificity 24·7 per cent, failure rate 2·4 per cent). Conclusion Women in the UK had a disproportionate risk of admission without surgical intervention and had high rates of normal appendicectomy. Risk prediction models to support shared decision‐making by identifying adults in the UK at low risk of appendicitis were identified

Comparing Ecosystem Model Outcomes Between Ixtoc 1 and \u3cem\u3eDeepwater Horizon\u3c/em\u3e Oil Spills

A spatially explicit biogeochemical Atlantis ecosystem model of the southern Gulf of Mexico was developed to simulate impacts from the Ixtoc 1 oil spill. Oil dispersion and concentration were estimated from satellite imagery and reported flow rates and a dose-response model applied to estimate impact on fish growth and mortality rates. Effects estimated for the Ixtoc 1 spill were compared with previously reported Atlantis ecological model simulations of the Deepwater Horizon (DWH) effects on the biomass of eight fish guilds. Biomass decreased sharply after the oil spill in both scenarios, compared to no-oil simulations, reaching minimum values within less than 2 years for most fish guilds. At the end of the 37-year simulation period, all fish guilds recovered to within 95% of the biomass of no-oil simulation for DWH, while all but one guild in the Ixtoc 1 simulation reached new equilibrium at less than 95% of the no-oil biomass. Comparison of the two oil spill simulations highlighted the important roles of starvation and juvenile mortality on fish stock biomass decrease