Warwick Medical School, University of Warwick, Coventry, UK
Warwick Medical School, University of Warwick, Coventry, UK.
BMJ Open. 2021 Feb 22;11(2):e044177. doi: 10.1136/bmjopen-2020-044177.
To estimate the test accuracy of faecal calprotectin (FC) for inflammatory bowel disease (IBD) in the primary care setting using routine electronic health records.
Retrospective cohort test accuracy study.
UK primary care.
5970 patients (≥18 years) without a previous IBD diagnosis and with a first FC test between 1 January 2006 and 31 December 2016. We excluded multiple tests and tests without numeric results in units of µg/g.
FC testing for the diagnosis of IBD. Disease status was confirmed by a recorded diagnostic code and/or a drug code of an IBD-specific medication at three time points after the FC test date.
Sensitivity, specificity, and positive and negative predictive values for the differential of IBD versus non-IBD and IBD versus irritable bowel syndrome (IBS) at the 50 and 100 µg/g thresholds.
5970 patients met the inclusion criteria and had at least 6 months of follow-up data after FC testing. 1897 had an IBS diagnosis, 208 had an IBD diagnosis, 31 had a colorectal cancer diagnosis, 80 had more than one diagnosis and 3754 had no subsequent diagnosis. Sensitivity, specificity, and positive and negative predictive values were 92.9% (88.6% to 95.6%), 61.5% (60.2% to 62.7%), 8.1% (7.1% to 9.2%) and 99.6% (99.3% to 99.7%), respectively, at the threshold of 50 µg/g. Raising the threshold to 100 µg/g missed less than 7% additional IBD cases. Longer follow-up had no effect on test accuracy. Overall, uncertainty was greater for specificity than sensitivity. General practitioners' (GPs') referral decisions did not follow the anticipated clinical pathways in national guidance.
GPs can be confident in excluding IBD on the basis of a negative FC test in a population with low pretest risk but should interpret a positive test with caution. The applicability of national guidance to general practice needs to be improved.
利用常规电子健康记录评估粪便钙卫蛋白（FC）在初级保健环境中用于炎症性肠病（IBD）的检测准确性。
回顾性队列检测准确性研究。
英国初级保健。
5970 名（≥18 岁）无既往 IBD 诊断且于 2006 年 1 月 1 日至 2016 年 12 月 31 日期间进行首次 FC 检测的患者。我们排除了多次检测和无数值结果（以 µg/g 为单位）的检测。
FC 检测用于 IBD 的诊断。疾病状态通过 FC 检测日期后三个时间点的记录诊断代码和/或 IBD 特异性药物的药物代码来确认。
50µg/g 和 100µg/g 界值时，IBD 与非 IBD 和 IBD 与肠易激综合征（IBS）的鉴别诊断的敏感度、特异度以及阳性和阴性预测值。
5970 名患者符合纳入标准，并且在 FC 检测后至少有 6 个月的随访数据。1897 名患者诊断为 IBS，208 名患者诊断为 IBD，31 名患者诊断为结直肠癌，80 名患者有多种诊断，3754 名患者无后续诊断。50µg/g 界值时，敏感度、特异度、阳性预测值和阴性预测值分别为 92.9%（88.6%至 95.6%）、61.5%（60.2%至 62.7%）、8.1%（7.1%至 9.2%）和 99.6%（99.3%至 99.7%）。将界值提高到 100µg/g 仅漏诊不到 7%的额外 IBD 病例。更长的随访时间对检测准确性没有影响。总体而言，特异度的不确定性大于敏感度。全科医生（GP）的转诊决策并未遵循国家指南中预期的临床路径。
在低术前风险人群中，基于阴性 FC 检测，GP 可以有信心排除 IBD，但应谨慎解读阳性检测结果。需要改进国家指南在一般实践中的适用性。
