Test accuracy of faecal calprotectin for inflammatory bowel disease in UK primary care: a retrospective cohort study of the IMRD-UK data

Early diagnosis of Crohn's disease in patients presenting with a perianal fistula: systematic review and development of a perianal red flags index

BACKGROUND

Delay in diagnosing Crohn's disease (CD) in patients presenting with perianal abscess (PAA) and/or fistula (PAF) is common. The aim of this study was to identify red flags suggestive of CD.

METHODS

A systematic literature review was conducted to identify symptoms associated with CD in patients presenting with PAA/PAF. A questionnaire including those symptoms, supplemented with items from the International Organization for the Study of Inflammatory Bowel Diseases (IO-IBD) red flags index for luminal CD, was administered to all adult patients presenting with a PAF and eventually diagnosed with CD and matched patients (1:3) from the same study period with a cryptoglandular PAF (2012-2023) at a single non-academic teaching hospital. All patients were asked to recall symptoms/signs experienced during their first PAF.

RESULTS

The systematic review identified 8 articles reporting on 15 clinical characteristics in patients presenting with PAA (n = 2)/PAF (n = 6), supplemented with 13 items from the IO-IBD red flags index (28 items in total). A total of 25 patients with CD and 75 patients with PAF without CD answered the questionnaire. Univariate analysis identified seven items associated with CD (age, family history, > 2 perianal interventions, weight loss, abdominal pain, diarrhoea and fatigue), and four items remained significant in multivariate analysis: age (OR 3.4 [1.0-11.5]), > 2 previous perianal interventions (OR 3.4 [1.0-10.1]), weight loss (OR 14.4 [3.7-55.6]) and abdominal pain (OR 9.8 [1.9-49.8]). Receiver-operating characteristic curve (ROC) analysis showed that a combination of these red flags was associated with good discrimination of CD versus non-CD (AUC 0.83 [0.72-0.94]).

CONCLUSIONS

The perianal red flags index has a good predictive value for early identification of patients with PAF at risk for underlying CD.

Fecal Nervonic Acid as a Biomarker for Diagnosing and Monitoring Inflammatory Bowel Disease

BACKGROUND/OBJECTIVES

Inflammatory bowel disease (IBD) is a chronic immune-mediated pathology associated with the dysregulation of lipid metabolism. The administration of nervonic acid, a very long-chain fatty acid, has been shown to improve colonic inflammation in a mouse model of colitis. Our study aimed to quantify fecal levels of nervonic acid, as well as the very long-chain fatty acids, lignoceric acid, and pentacosanoic acid, to identify associations with IBD activity.

METHODS

Stool samples were collected from 62 patients with IBD and 17 healthy controls. Nervonic acid, lignoceric acid, and pentacosanoic acid were quantified by gas chromatography coupled with mass spectrometry (GC-MS). Lipid levels, normalized to the dry weight of fecal homogenates, were used for calculations.

RESULTS

Patients with IBD exhibited elevated fecal nervonic acid levels compared to healthy controls, with no significant differences observed between ulcerative colitis and Crohn's disease. A fecal nervonic acid concentration of 0.49 µmol/g distinguished IBD patients from controls, achieving a sensitivity of 71% and a specificity of 82%. Fecal nervonic acid levels showed a positive correlation with both C-reactive protein and fecal calprotectin and increased proportionally with rising fecal calprotectin levels. IBD patients treated with corticosteroids or interleukin-12/23 antibodies had higher levels of fecal nervonic acid than those in other therapies, with no difference in serum C-reactive protein and calprotectin levels between these groups.

CONCLUSIONS

In summary, this analysis indicates that fecal nervonic acid may emerge as a novel specific biomarker for IBD diagnosis and disease monitoring.

Frequency of irritable bowel syndrome in spondyloarthritis: a multicentric cross-sectional study and meta-analysis

OBJECTIVE

To evaluate the prevalence of symptoms and factors associated with irritable bowel syndrome (IBS) in axial spondyloarthritis (ax-SpA).

METHODS

In a cross-sectional multicentric study, consecutive patients with ax-SpA treated with biologics in five rheumatology departments were asked for IBS Rome IV criteria. Demographic data, lifestyle behaviours and disease characteristics were recorded. Second, a systematic literature review and meta-analysis were performed following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

RESULTS

Of the 500 patients with ax-SpA included, 124 reported IBS symptoms (25%). Female gender, unemployment, higher Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and worse Bath Ankylosing Spondylitis Functional Index scores, multiple lines of biologics, fibromyalgia, anxiety, depression and lower physical activity were associated with IBS symptoms. In multivariate model, the risk of IBS was associated with anxiety and physical inactivity. From the literature review, the prevalence of IBS in patients with SpA was 15.4% (8.8% to 23.3%). Meta-analysis of the five studies comparing the presence of IBS in patients with SpA (323/7292) and healthy controls (484/35587) showed a significant increase of IBS in patients with SpA (OR=1.59 (1.05 to 2.40)).

CONCLUSION

The prevalence of IBS symptoms was high in the ax-SpA population and should therefore be considered in the presence of gastrointestinal disorders. The presence of IBS symptoms was associated with anxiety and low physical activity in multivariate analysis. Patients with IBS symptoms tended to have more difficult to manage disease characterised by higher activity, worse functional score and multiple lines of treatment in univariate analysis.

Fecal short chain fatty acids and urinary 3-indoxyl sulfate do not discriminate between patients with Crohn´s disease and ulcerative colitis and are not of diagnostic utility for predicting disease severity

BACKGROUND

Urinary 3-indoxyl sulfate levels as well as fecal short chain fatty acid (SCFA) concentrations are surrogate markers for gut microbiota diversity. Patients with inflammatory bowel diseases (IBDs) and patients with primary sclerosing cholangitis (PSC), a disease closely associated with IBD, have decreased microbiome diversity. In this paper, the fecal SCFAs propionate, acetate, butyrate and isobutyrate of patients with IBD and patients with PSC-IBD and urinary 3-indoxyl sulfate of IBD patients were determined to study associations with disease etiology and severity.

METHODS

SCFA levels in feces of 64 IBD patients and 20 PSC-IBD patients were quantified by liquid chromatography with tandem mass spectrometry (LC-MS/MS). Urinary 3-indoxyl sulfate levels of 45 of these IBD patients were analysed by means of reversed-phase liquid chromatography-electrospray ionization-tandem mass spectrometry. Feces of 17 healthy controls and urine of 13 of these controls were analyzed in parallel. These cohorts had comparable sex distribution and age.

RESULTS

Urinary 3-indoxyl sulfate concentrations (normalized to urinary creatinine levels) was increased (P = 0.030) and fecal isobutyrate levels (normalized to dry weight of the stool sample) of IBD patients were decreased (P = 0.035) in comparison to healthy controls. None of the analyzed metabolites differed between patients with Crohn´s disease (CD) and patients with ulcerative colitis (UC). Fecal acetate and butyrate positively correlated with fecal calprotectin (P = 0.040 and P = 0.005, respectively) and serum C-reactive protein (P = 0.024 and P = 0.025, respectively) in UC but not CD patients. UC patients with fecal calprotectin levels above 150 µg/g, indicating intestinal inflammatory activity, had higher fecal acetate (P = 0.016), butyrate (P = 0.007) and propionate (P = 0.046) in comparison to patients with fecal calprotectin levels < 50 µg/g. Fecal SCFA levels of PSC-IBD and IBD patients were comparable.

CONCLUSIONS

Current findings suggest that analysis of urinary 3-indoxyl-sulfate as well as fecal SCFAs has no diagnostic value for IBD and PSC-IBD diagnosis or monitoring of disease severity.

Diagnostic value of fecal calprotectin in primary care patients with gastrointestinal symptoms: A retrospective Swedish cohort study

Aims

To investigate the diagnostic accuracy of fecal calprotectin (FC) for inflammatory bowel disease (IBD) and organic gastrointestinal disease (OGID) in primary care. To examine the association with demographic factors, symptoms and concomitant medical therapy.

Methods

A retrospective analysis of data on all semiquantitative FC tests from individuals ≥18 years conducted in primary care in Östergötland County in 2010. A 5-year follow-up with inclusion of new gastrointestinal diagnoses.

Results

A total of 1293 eligible patients were included. IBD was found in 8.8% and other OGID in 30.8% of patients with positive FC. Positive FC was associated with diarrhea, age >60 years, duration <3 months, use of nonsteroidal anti-inflammatory drug (NSAID), and proton pump inhibitor (PPI). Predictors of IBD were positive FC, diarrhea, rectal bleeding, and male sex; predictors of OGID positive FC, age >35 years, abnormal clinical findings, and duration <3 months. FC yielded the highest sensitivity and negative predictive value compared with demographic factors, symptoms, and duration. Use of NSAID and PPI showed a marginal increase in the sensitivity, positive predictive value, and decrease in the specificity of FC. Within 5 years, 4.0% had a new gastrointestinal diagnosis among patients with positive FC (0.6% IBD).

Conclusions

FC reliably rules out IBD and contradicts the presence of other OGID in primary care patients. Positive FC test together with other predictors, such as diarrhea, rectal bleeding, short duration, or age >35 years, should encourage a prioritized investigation. Use of NSAID, PPI, and ASA may affect the diagnostic accuracy of FC for IBD and OGID.

Italian guidelines for the management of irritable bowel syndrome: Joint Consensus from the Italian Societies of: Gastroenterology and Endoscopy (SIGE), Neurogastroenterology and Motility (SINGEM), Hospital Gastroenterologists and Endoscopists (AIGO), Digestive Endoscopy (SIED), General Medicine (SIMG), Gastroenterology, Hepatology and Pediatric Nutrition (SIGENP) and Pediatrics (SIP)

The irritable bowel syndrome (IBS) is a chronic disorder of gut-brain interaction. IBS is still associated with areas of uncertainties, especially regarding the optimal diagnostic work-up and the more appropriate management. Experts from 7 Italian Societies conducted a Delphi consensus with literature summary and voting process on 27 statements. Recommendations and quality of evidence were evaluated using the grading of recommendations, assessment, development, and evaluation (GRADE) criteria. Consensus was defined as >80% agreement and reached for all statements. In terms of diagnosis, the consensus supports a positive diagnostic strategy with a symptom-based approach, including the psychological comorbidities assessment and the exclusion of alarm symptoms, together with the digital rectal examination, full blood count, C-reactive protein, serology for coeliac disease, and fecal calprotectin assessment. Colonoscopy should be recommended in patients with alarm features. Regarding treatment, the consensus strongly supports a dietary approach for patients with IBS, the use of soluble fiber, secretagogues, tricyclic antidepressants, psychologically directed therapies and, only in specific IBS subtypes, rifaximin. A conditional recommendation was achieved for probiotics, polyethylene glycol, antispasmodics, selective serotonin reuptake inhibitors and, only in specific IBS subtypes, 5-HT3 antagonists, 5-HT4 agonists, bile acid sequestrants.

Natriuretic peptide testing and heart failure diagnosis in primary care: diagnostic accuracy study

BACKGROUND

Natriuretic peptide (NP) testing is recommended for patients presenting to primary care with symptoms of chronic heart failure (HF) to prioritise referral for diagnosis.

AIM

To report NP test performance at European Society of Cardiology (ESC) and National Institute for Health and Care Excellence (NICE) guideline referral thresholds.

DESIGN AND SETTING

Diagnostic accuracy study using linked primary and secondary care data (2004 to 2018).

METHOD

The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of NP testing for HF diagnosis was assessed.

RESULTS

In total, 229 580 patients had an NP test and 21 102 (9.2%) were diagnosed with HF within 6 months. The ESC NT-proBNP threshold ≥125 pg/mL had a sensitivity of 94.6% (95% confidence interval [CI] = 94.2 to 95.0) and specificity of 50.0% (95% CI = 49.7 to 50.3), compared with sensitivity of 81.7% (95% CI = 81.0 to 82.3) and specificity of 80.3% (95% CI = 80.0 to 80.5) for the NICE NT-proBNP ≥400 pg/mL threshold. PPVs for an NT-proBNP test were 16.4% (95% CI = 16.1 to 16.6) and 30.0% (95% CI = 29.6 to 30.5) for ESC and NICE thresholds, respectively. For both guidelines, nearly all patients with an NT-proBNP level below the threshold did not have HF (NPV: ESC 98.9%, 95% CI = 98.8 to 99.0 and NICE 97.7%, 95% CI = 97.6 to 97.8).

CONCLUSION

At the higher NICE chronic HF guideline NP thresholds, one in five cases are initially missed in primary care but the lower ESC thresholds require more diagnostic assessments. NP is a reliable 'rule-out' test at both cut-points. The optimal NP threshold will depend on the priorities and capacity of the healthcare system.

Comparing outcomes from tailored meta-analysis with outcomes from a setting specific test accuracy study using routine data of faecal calprotectin testing for inflammatory bowel disease

Background

Meta-analyses of test accuracy studies may provide estimates that are highly improbable in clinical practice. Tailored meta-analysis produces plausible estimates for the accuracy of a test within a specific setting by tailoring the selection of included studies compatible with a specific setting using information from the target setting. The aim of this study was to validate the tailored meta-analysis approach by comparing outcomes from tailored meta-analysis with outcomes from a setting specific test accuracy study.

Methods

A retrospective cohort study of primary care electronic health records provided setting-specific data on the test positive rate and disease prevalence. This was used to tailor the study selection from a review of faecal calprotectin testing for inflammatory bowel disease for meta-analysis using the binomial method and the Mahalanobis distance method. Tailored estimates were compared to estimates from a study of test accuracy in primary care using the same routine dataset.

Results

Tailoring resulted in the inclusion of 3/14 (binomial method) and 9/14 (Mahalanobis distance method) studies in meta-analysis. Sensitivity and specificity from tailored meta-analysis using the binomial method were 0.87 (95% CI 0.77 to 0.94) and 0.65 (95% CI 0.60 to 0.69) and 0.98 (95% CI 0.83 to 0.999) and 0.68 (95% CI 0.65 to 0.71), respectively using the Mahalanobis distance method. The corresponding estimates for the conventional meta-analysis were 0.94 (95% CI 0.90 to 0.97) and 0.67 (95% CI 0.57 to 0.76) and for the FC test accuracy study of primary care data 0.93 (95%CI 0.89 to 0.96) and 0.61 (95% CI 0.6 to 0.63) to detect IBD at a threshold of 50 μg/g. Although the binomial method produced a plausible estimate, the tailored estimates of sensitivity and specificity were not closer to the primary study estimates than the estimates from conventional meta-analysis including all 14 studies.

Conclusions

Tailored meta-analysis does not always produce estimates of sensitivity and specificity that lie closer to the estimates derived from a primary study in the setting in question. Potentially, tailored meta-analysis may be improved using a constrained model approach and this requires further investigation.

Faecal calprotectin testing in UK general practice: a retrospective cohort study using The Health Improvement Network database

BACKGROUND

Faecal calprotectin (FC) testing to detect inflammatory bowel disease (IBD) was recommended for use in UK general practice in 2013. The actual use of FC testing following the national recommendations is unknown.

AIM

To characterise the use of FC testing for IBD in UK general practice.

DESIGN AND SETTING

A retrospective cohort study of routine electronic patient records from The Health Improvement Network database from UK general practice.

METHOD

The study included 6 965 853 adult patients (aged ≥18 years), between 2006 and 2016. FC test uptake, the patients tested, and patient management following testing were characterised.

RESULTS

A total of 17 027 patients had 19 840 FC tests recorded. The mean age of tested patients was 44.2 years. The first FC tests were documented in 2009. FC test use was still increasing in 2016. By 2016, 66.8% (n = 493/738) of practices had started FC testing. About one-fifth (20.7%, n = 1253/6051) of tests were carried out in patients aged ≥60 years. Only 7.8% (n = 473/6051) of the FC test records were preceded by symptoms eligible for FC testing. Only 3.1% (n = 1720/55 477) of patients with eligible symptoms have received FC testing since the national recommendations were published. There was only a small number of patients with symptoms, FC test, and a IBD diagnosis. In total, 71.3% (n = 1416/1987) of patients with a positive and 47.7% (n = 1337/2805) with a negative FC test were referred or further investigated.

CONCLUSION

Uptake of FC testing in clinical practice has been slow and inconsistent. The indication of non-compliance with national recommendations may suggest that these recommendations lack applicability to the general practice context.