BACKGROUND Complicated intra-abdominal infections (cIAIs) are associated with significant morbidity and mortality. The aim of this study was to describe the clinical characteristics of patients with cIAI in a multicentre study and to develop clinical prediction models (CPMs) to help identify patients at risk of mortality or relapse. METHODS A multicentre observational study was conducted from August 2016 to February 2017 in the UK. Adult patients diagnosed with cIAI were included. Multivariable logistic regression was performed to develop CPMs for mortality and cIAI relapse. The c-statistic was used to test model discrimination. Model calibration was tested using calibration slopes and calibration in the large (CITL). The CPMs were then presented as point scoring systems and validated further. RESULTS Overall, 417 patients from 31 surgical centres were included in the analysis. At 90 days after diagnosis, 17.3 per cent had a cIAI relapse and the mortality rate was 11.3 per cent. Predictors in the mortality model were age, cIAI aetiology, presence of a perforated viscus and source control procedure. Predictors of cIAI relapse included the presence of collections, outcome of initial management, and duration of antibiotic treatment. The c-statistic adjusted for model optimism was 0.79 (95 per cent c.i. 0.75 to 0.87) and 0.74 (0.73 to 0.85) for mortality and cIAI relapse CPMs. Adjusted calibration slopes were 0.88 (95 per cent c.i. 0.76 to 0.90) for the mortality model and 0.91 (0.88 to 0.94) for the relapse model; CITL was -0.19 (95 per cent c.i. -0.39 to -0.12) and - 0.01 (- 0.17 to -0.03) respectively. CONCLUSION Relapse of infection and death after complicated intra-abdominal infections are common. Clinical prediction models were developed to identify patients at increased risk of relapse or death after treatment, these now require external validation.

中文翻译：

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复杂腹腔内感染预后的临床预测模型的开发和内部验证。

背景技术复杂的腹腔内感染（cIAIs）与明显的发病率和死亡率相关。这项研究的目的是在一项多中心研究中描述cIAI患者的临床特征，并开发临床预测模型（CPM）以帮助确定有死亡或复发风险的患者。方法于2016年8月至2017年2月在英国进行了一项多中心观察性研究。包括诊断为cIAI的成年患者。进行多变量logistic回归以开发用于死亡率和cIAI复发的CPM。c统计量用于测试模型判别。使用校准斜率和大范围校准（CITL）对模型校准进行了测试。然后将CPM作为点数评分系统提出，并进行进一步验证。结果总体而言，来自31个手术中心的417名患者被纳入分析。诊断后90天，cIAI复发率为17.3％，死亡率为11.3％。死亡率模型的预测因素是年龄，cIAI病因，是否有穿孔粘液和源控制程序。cIAI复发的预测因素包括收集物的存在，初始治疗的结果以及抗生素治疗的持续时间。调整后的模型乐观度的c统计量为0.79（95％ci为0.75至0.87），死亡率和cIAI复发CPM为0.74（0.73至0.85）。死亡率模型的校正校准斜率为0.88（95％ci为0.76至0.90），复发模型的校正校正斜率为0.91（0.88至0.94）。CITL分别为-0.19（95％ci -0.39至-0.12）和-0.01（-0.17至-0.03）。结论复杂的腹腔内感染常导致感染复发和死亡。已开发出临床预测模型来识别治疗后复发或死亡风险增加的患者，这些现在需要外部验证。