Fecal Calprotectin as a Selection Tool for Small Bowel Capsule Endoscopy in Suspected Crohn's Disease

Fecal calprotectin as an inflammatory biomarker in small bowel Crohn disease

Background

Small bowel capsule endoscopy (SBCE) is an essential tool for evaluation of small bowel (SB) Crohn disease (CD). Fecal calprotectin (FC) represents an important biomarker of intestinal inflammation, widely used in ulcerative colitis and CD. Our aim was to evaluate the role of FC for diagnosing inflammatory activity in patients with isolated SB CD and how it correlates with SBCE findings.

Methods

This is a retrospective study conducted in a tertiary inflammatory bowel disease referral center that included patients with SB CD who underwent SBCE between January 2017 and February 2023. FC value was obtained from the closest stool examination to SBCE.

Results

One hundred ninety-six patients were included: 123 were women (63%) with a mean age of 44.2 years. In the SBCE, 127 (65%) patients had a Lewis Score ≥135 and, among the 94 patients with FC >200 μg/g, 23 had LS <135, 36 had LS between 135 and 790, and 35 had LS ≥790. FC levels were predictive of endoscopic lesions in SBCE, with significant correlation between FC level and total LS (Pearson correlation coefficient 0.43, P<.001). The sensitivity and specificity were calculated for each cut-off value being respectively 78% and 45% for FC = 100 μg/g, 69% and 59% for FC = 150 μg/g and 67% and 67% for FC = 200 μg/g.

Conclusion

FC showed moderate correlation with endoscopic findings in SBCE in SB CD. It is, therefore, a reasonable marker for predicting significant inflammatory lesions in SBCE; however, none of the cut-off had a high sensitivity or specificity.

Clinical value of fecal calprotectin for evaluating disease activity in patients with Crohn's disease

Objective: To explore the clinical value of fecal calprotectin (FC) for evaluating disease activity in patients with Crohn's disease (CD) and its relationship with disease location. Methods: Patients with CD were enrolled retrospectively, and clinical data, including FC levels, were collected. Clinical activity was assessed using the Crohn's disease activity index (CDAI). Endoscopic activity was assessed using a simple endoscopic score for Crohn's disease (SES-CD). The partial SES-CD (pSES-CD) was scored for the size of ulcers in each segment as defined by the SES-CD and was calculated as the sum of segmental ulcer scores. Results: This study included 273 CD patients. The FC level was significantly positively correlated with the CDAI and SES-CD, with correlation coefficients of 0.666 and 0.674, respectively. The median FC levels in patients with clinical remission and mildly active and moderately-severely active disease were 41.01, 164.20, and 444.45 μg/g. These values were 26.94, 66.77, and 327.22 μg/g during endoscopic remission and mildly and moderately-severely active stages, respectively. Compared with c-reactive protein (CRP), the erythrocyte sedimentation rate (ESR), and other biomarker parameters, FC was better at predicting disease activity for CD patients. For an FC <74.52 μg/g, the area under the curve (AUC) for predicting clinical remission was 0.86, with a sensitivity of 89.47% and a specificity of 71.70%. Moreover, endoscopic remission was predicted with a sensitivity of 68.02% and a specificity of 85.53%. The AUC was 0.83, and the cutoff value was 80.84 μg/g. In patients with ileal and (ileo) colonic CD, FC was significantly correlated with the CDAI, SES-CD, and pSES-CD. The correlation coefficients were 0.711 (CDAI), 0.473 (SES-CD), and 0.369 (pSES-CD) in patients with ileal CD and 0.687, 0.745, and 0.714 in patients with (ileo) colonic CD, respectively. For patients in remission, those in the active stage, and those with large or very large ulcers, differences in FC levels were not significant between patients with ileal and (ileo) colonic CD. Conclusion: FC is a reliable predictor of disease activity in patients with CD, including those with ileal CD. FC is thus recommended for the routine follow-up of patients with CD.

Small-bowel capsule endoscopy and device-assisted enteroscopy for diagnosis and treatment of small-bowel disorders: European Society of Gastrointestinal Endoscopy (ESGE) Guideline - Update 2022

MR1: ESGE recommends small-bowel capsule endoscopy as the first-line examination, before consideration of other endoscopic and radiological diagnostic tests for suspected small-bowel bleeding, given the excellent safety profile of capsule endoscopy, its patient tolerability, and its potential to visualize the entire small-bowel mucosa.Strong recommendation, moderate quality evidence. MR2: ESGE recommends small-bowel capsule endoscopy in patients with overt suspected small-bowel bleeding as soon as possible after the bleeding episode, ideally within 48 hours, to maximize the diagnostic and subsequent therapeutic yield.Strong recommendation, high quality evidence. MR3: ESGE does not recommend routine second-look endoscopy prior to small-bowel capsule endoscopy in patients with suspected small-bowel bleeding or iron-deficiency anemia.Strong recommendation, low quality evidence. MR4: ESGE recommends conservative management in those patients with suspected small-bowel bleeding and high quality negative small-bowel capsule endoscopy.Strong recommendation, moderate quality evidence. MR5: ESGE recommends device-assisted enteroscopy to confirm and possibly treat lesions identified by small-bowel capsule endoscopy.Strong recommendation, high quality evidence. MR6: ESGE recommends the performance of small-bowel capsule endoscopy as a first-line examination in patients with iron-deficiency anemia when small bowel evaluation is indicated.Strong recommendation, high quality evidence. MR7: ESGE recommends small-bowel capsule endoscopy in patients with suspected Crohn's disease and negative ileocolonoscopy findings as the initial diagnostic modality for investigating the small bowel, in the absence of obstructive symptoms or known bowel stenosis.Strong recommendation, high quality evidence. MR8: ESGE recommends, in patients with unremarkable or nondiagnostic findings from dedicated small-bowel cross-sectional imaging, small-bowel capsule endoscopy as a subsequent investigation if deemed likely to influence patient management.Strong recommendation, low quality evidence. MR9: ESGE recommends, in patients with established Crohn's disease, the use of a patency capsule before small-bowel capsule endoscopy to decrease the capsule retention rate.Strong recommendation, moderate quality evidence. MR10: ESGE recommends device-assisted enteroscopy (DAE) as an alternative to surgery for foreign bodies retained in the small bowel requiring retrieval in patients without acute intestinal obstruction.Strong recommendation, moderate quality evidence. MR11: ESGE recommends DAE-endoscopic retrograde cholangiopancreatography (DAE-ERCP) as a first-line endoscopic approach to treat pancreaticobiliary diseases in patients with surgically altered anatomy (except for Billroth II patients).Strong recommendation, moderate quality evidence.

Isotretinoin-Induced Distal Ileitis Mimicking Crohn's Disease

Terminal ileitis is a common condition defined as inflammation of the terminal portion of the ileum, which is typically associated with inflammatory bowel disease (IBD), classically Crohn's disease (CD). However, it can have other etiologies, including drug-induced ones. Isotretinoin is an effective and commonly used treatment for acne vulgaris, presenting multiple adverse effects. There have been discussions over its association with enteric inflammation, particularly over IBD emergence risk. We report a case of a previously healthy 17-year-old female who presented transitory clinical, laboratory, imaging, and endoscopic evidence of distal ileitis, temporally related to extended isotretinoin treatment and mimicking CD. Repeated clinical, laboratory, imaging, and endoscopic reassessment after isotretinoin discontinuation confirmed an almost complete resolution of the condition, avoiding IBD misdiagnosis and specific medication initiation. Our case highlights the differential diagnosis of ileitis as being of critical importance to avoid further unnecessary diagnostic investigations and inadequate treatment. Serial re-evaluation may be of key importance to reach a final diagnosis. Although recent literature suggests that isotretinoin is not associated with an increased IBD risk, our case highlights the possibility of it inducing small bowel injury and inflammation, similar to what has been reported with other drugs.

Fecal calprotectin in predicting small bowel capsule endoscopy findings in pediatric patients with known Crohn's disease

Fecal calprotectin (FC) has been proposed as a noninvasive surrogate marker of intestinal inflammation in inflammatory bowel disease. This study aimed to assess the capability of FC in predicting small bowel capsule endoscopy (SBCE) findings in pediatric patients with known Crohn's disease (CD). We retrieved data of consecutive patients aged 2 to 17 years old with established CD who underwent SBCE from Janurary 2017 to April 2020 and had endoscopic remission on ileocolonoscopy. Sixty-eight patients were included in the analysis. There were 13 patients with a weighted pediatric CD activity index ≥ 12.5, 47 patients with FC ≥ 200 µg/g, and 45 patients with significant small bowel (SB) inflammation [Lewis score (LS) ≥ 135]. The LS correlated weakly with FC (R = 0.30, P < .05). The area under the curve of FC as a surrogate diagnostic test for LS ≥ 135 was 0.691, and the optimal FC cutoff values were 242 µg/g with the corresponding sensitivity and specificity of 78% and 65%, respectively. The area under the curve of FC for moderate-to-severe inflammatory activity in the SB was 0.718. In patients with FC level ≥ 670 µg/g, LS ≥ 790 was found in 33% (9/27) of patients, with the sensitivity and specificity of 69% and 67%, respectively. FC may be used to predict SB mucosal inflammation in pediatric patients with confirmed CD having endoscopic remission on ileocolonoscopy.

Faecal calprotectin increases the diagnostic yield in patients with suspected small bowel disease - a multicenter retrospective cohort study

AIM OF THE STUDY

Diagnosing small bowel pathology is challenging, and the diagnostic yield of small bowel capsule endoscopy is highly variable. Faecal calprotectin is a non-invasive intestinal inflammation marker that could be used as a selection tool to identify patients who might benefit from small bowel capsule endoscopy and increase its diagnostic yield. This study aimed to investigate the value of faecal calprotectin in detecting small bowel lesions in an unselected patient population.

METHODS

We performed a retrospective analysis of consecutive patients who underwent small bowel capsule endoscopy at the University Hospital Basel and the University Medical Clinic Cantonal Hospital Baselland, Switzerland, between 2010 and 2018. Patients without faecal calprotectin testing were excluded from the analysis. The primary endpoint was the presence of a clinically significant small bowel finding.

RESULTS

Patients with positive faecal calprotectin results were more likely to have small bowel findings (66.7% vs 39.4%; P = 0.007). The optimal faecal calprotectin cut-off to identify clinically significant small bowel lesions was 63 μg/g with 78.3% (95% confidence interval: 66.7-87.9) sensitivity, 47.9% (33.3-62.8) specificity, 1.50 (1.1-2.0) positive and 0.45 (0.3-0.8) negative likelihood ratios, 68.4% (61.6-74.4) positive and 60.5% (47.3-72.4) negative predictive values, and 65.0% overall accuracy. Faecal calprotectin performed best in patients with suspected inflammatory bowel disease, with 66.7% (48.2-82.0) sensitivity, 70.6% (44.0-89.7) specificity, 2.27 (1.0-4.9) positive and 0.47 (0.3-0.8) negative likelihood ratios, 81.5% (67.0-90.5) positive and 54.5% (39.7-68.6) negative predictive values, and 71.4% overall accuracy.

CONCLUSION

Faecal calprotectin testing increases the diagnostic yield of small bowel capsule endoscopy and may help identify patients at risk of small bowel disease.

Capsule Endoscopy in Inflammatory Bowel Disease: When? To Whom?

Capsule endoscopy (CE) has proven to be a valuable diagnostic modality for small bowel diseases over the past 20 years, particularly Crohn's disease (CD), which can affect the entire gastrointestinal tract from the mouth to the anus. CE is not only used for the diagnosis of patients with suspected small bowel CD, but can also be used to assess disease activity, treat-to-target, and postoperative recurrence in patients with established small bowel CD. As CE can detect even mildly non-specific small bowel lesions, a high diagnostic yield is not necessarily indicative of high diagnostic accuracy. Moreover, the cost effectiveness of CE as a third diagnostic test employed usually after ileocolonoscopy and MR or CT enterography is an important consideration. Recently, new developments in colon capsule endoscopy (CCE) have increased the utility of CE in patients with ulcerative colitis (UC) and pan-enteric CD. Although deflation of the colon during the examination and the inability to evaluate dysplasia-associated lesion or mass results in an inherent risk of overestimation or underestimation, the convenience of CCE examination and the risk of flare-up after colonoscopy suggest that CCE could be used more actively in patients with UC.

Assessment of a new score for capsule endoscopy in pediatric Crohn's disease (CE-CD)

Background and study aims  Two scores have been implemented to standardize capsule endoscopic (CE) findings in patients with Crohn's disease (CD): Lewis score (LS) and Capsule Endoscopy Crohn's Disease Activity Index (CECDAI). Both have limitations and are not well validated in the pediatric population. The aim of our study was to assess a new score (capsule endoscopy - Crohn's disease index, CE-CD) in pediatric patients with CD and to compare it to preexisting scores. Patients and methods  This was a double-center, retrospective study involving pediatric subjects with CD who underwent CE. Correlation analyses between CE-CD, endoscopy scores and noninvasive markers of disease activities were performed. The ability of different CE scores to predict clinical and endoscopic outcomes was evaluated with regression and survival analyses. Results  A total of 312 subjects were analyzed. The CE-CD score showed a moderate (Pearson's r = 0.581, P  < 0.001) and strong (r = 0.909, P  < 0.001) association with LS and CECDAI, respectively. CE-CD was a statistically significant predictor of hospitalization (hazard ratio [HR]1.061), treatment escalation (HR 1.062), steroid therapy (HR 1.082), clinical (HR 1.064) and endoscopic (HR 1.060) relapse over the twenty-four months ( P  < 0.001). Subjects with mucosal inflammation according to CE-CD (CE-CD ≥ 9) had worse outcomes compared to patients without inflammation (CE-CD < 9) (Log rang test < 0.001). Conclusions  The CE-CD score is a simple, reliable, reproducible, and predictive score for evaluation of small bowel inflammation in pediatric patients with CD. Prospective validation is needed to confirm the applicability of this new index in clinical practice.

Diagnostic Accuracy of Fecal Calprotectin for the Detection of Small Bowel Crohn's Disease through Capsule Endoscopy: An Updated Meta-Analysis and Systematic Review

Background/Aims

The diagnosis of small bowel Crohn's disease with negative ileocolonoscopic findings has been challenging. Fecal calprotectin (FC) has been used to detect colonic inflammation, but its efficacy for detecting small bowel inflammation is less established. We performed an updated meta-analysis to evaluate the diagnostic accuracy of FC to detect active small bowel inflammation observed during capsule endoscopy.

Methods

We conducted a systematic literature search for studies that evaluated the correlation between small bowel inflammation and FC in patients with suspected/established Crohn's disease. We calculated the pooled sensitivity, specificity, and diagnostic odds ratios (DORs) and constructed hierarchical summary receiver operating characteristic curves for FC cutoffs of 50, 100, and 200 μg/g.

Results

Fourteen studies were eligible for the final analysis. The DORs of all FC cutoffs were significant. The highest DOR was observed at 100 μg/g (sensitivity, 0.73; specificity, 0.73; and DOR, 7.89) and was suggested as the optimal diagnostic cutoff. If we analyzed only studies that included patients with suspected Crohn's disease, the DOR was 8.96. If we analyzed only studies that included patients with a Lewis score ≥135 as a diagnostic criterion for active disease, the DOR was 10.90.

Conclusions

FC has significant diagnostic accuracy for detecting small bowel inflammation, and an FC cutoff of 100 μg/g can be used as a tool to screen for small bowel Crohn's disease.

Role of capsule endoscopy in inflammatory bowel disease: Anything new?

Capsule endoscopy (CE) is a recently developed diagnostic method for diseases of the small bowel that is non-invasive, safe, and highly tolerable. Its role in patients with inflammatory bowel disease has been widely validated in suspected and established Crohn’s disease (CD) due to its ability to assess superficial lesions not detected by cross-sectional imaging and proximal lesions of the small bowel not evaluable by ileocolonoscopy. Because CE is a highly sensitive but less specific technique, differential diagnoses that can simulate CD must be considered, and its interpretation should be supported by other clinical and laboratory indicators. The use of validated scoring systems to characterize and estimate lesion severity (Lewis score, Capsule Endoscopy Crohn’s Disease Activity Index), as well as the standardization of the language used to define the lesions (Delphi Consensus), have reduced the interobserver variability in CE reading observed in clinical practice, allowing for the optimization of diagnoses and clinical management strategies. The appearance of the panenteric CE, the incorporation of artificial intelligence, magnetically-guided capsules, and tissue biopsies are elements that contribute to CE being a promising, unique diagnostic tool in digestive tract diseases.

From terminal ileitis to Crohn's disease: how capsule endoscopy is crucial to diagnosis

BACKGROUND AND AIMS

Terminal ileitis is a common condition and may be associated with a wide variety of diseases, mostly Crohn's disease. Although small bowel capsule endoscopy (SBCE) is a valuable diagnostic tool for small-bowel diseases, data regarding its diagnostic impact on isolated terminal ileitis are sparse. The aim of this study was to evaluate the diagnostic value of SBCE for isolated terminal ileitis detected during ileocolonoscopy and to assess predictive factors for Crohn's disease diagnosis.

METHODS

This is a retrospective study including consecutive patients undergoing SBCE after diagnosis of terminal ileitis without colonic mucosal abnormalities on ileocolonoscopy between January 2016 and September 2019.

RESULTS

This included 102 patients with isolated terminal ileitis on ileocolonoscopy. Positive findings on SBCE were found in 82.4% of patients. After performing SBCE, 61.8% of patients had a final diagnosis, being Crohn's disease the most common (34.3%), followed by NSAIDs enteropathy (12.7%). Extraintestinal manifestations (P = 0.003), weight loss (P = 0.02), abnormal imaging (P = 0.04) and positive SBCE findings (P = 0.001) were independently associated with Crohn's disease diagnosis. Regarding SBCE, presence of proximal small-bowel disease (P = 0.02), diffuse findings (P = 0.002) and moderate to severe inflammatory activity (Lewis score ≥ 790) (P < 0.001) were independently associated with Crohn's disease diagnosis.

CONCLUSION

SBCE is a valuable tool that should be systematically used in patients with isolated terminal ileitis on ileocolonoscopy, since it revealed a high diagnostic yield, supporting a definite diagnosis in almost two-thirds of patients, and Crohn's disease diagnosis in approximately one-third of patients. A diagnosis of Crohn's disease should be considered when a patient with terminal ileitis on ileocolonoscopy shows proximal involvement, diffuse findings and/or moderate to severe inflammatory activity on SBCE.

Role of Capsule Endoscopy in Inflammatory Bowel Disease

In Crohn disease (CD), the use of capsule endoscopy (CE) for suspected versus established disease is very different. Most patients with CD are diagnosed with ileocolonoscopy. In patients with a negative ileocolonoscopy, CE is the next best test in suspected CD. In patients with established CD, the potential benefits of CE are rating severity of disease, establishing extent and distribution, and following mucosal healing in a treat to target strategy. In those with proximal small bowel disease, CE can help in diagnosis and prognostication. In ulcerative colitis, CE has a limited role, but that may change with evolving technology.

Capsule endoscopy - Recent developments and future directions

INTRODUCTION

Capsule endoscopy (CE) is an established modality in the diagnostic algorithm of small bowel (SB) pathology. Its use has expanded for investigation of upper and lower gastrointestinal diseases with similar prototypes.

AREAS COVERED

This review covers the role and recent advances of CE, as a non-invasive investigative tool.

EXPERT OPINION

The use of upper gastrointestinal CE is useful in patients who require surveillance for varices particularly in the current era of the COVID-19 pandemic. It has also shown high accuracy in the detection of upper gastrointestinal hemorrhage in patients presenting with a suspicion of hemorrhage. Findings on CE help to guide further management by device-assisted enteroscopy. The data on colon CE suggest comparable diagnostic accuracy to colonoscopy for polyp detection; however, more evidence is required in the high-risk group. Crohn's CE has become an integral part of the management of patients with Crohn's disease offering a comparative assessment tool post escalation of therapy. Artificial intelligence within CE has demonstrated similar if not better diagnostic yield compared to the human with a significantly shorter reading time. Artificial intelligence is likely to be in-built within CE reading platforms over the next few years minimizing reporting time and human error.

Assessment of disease activity in inflammatory bowel diseases: Non-invasive biomarkers and endoscopic scores

Inflammatory bowel diseases (IBD) comprise two major forms: Crohn's disease and ulcerative colitis. The diagnosis of IBD is based on clinical symptoms combined with results found in endoscopic and radiological examinations. In addition, the discovery of biomarkers has significantly improved the diagnosis and management of IBD. Several potential genetic, serological, fecal, microbial, histological and immunological biomarkers have been proposed for IBD, and they have been evaluated for clinical routine and clinical trials. Ileocolonoscopy, especially with biopsy collection, has been considered the standard method to diagnose IBD and to assess clinical activity of the disease, but it is limited to the colon and terminal ileum and is considered invasive. For this reason, non-invasive biomarkers are necessary for this type of chronic inflammatory disease, which affects mostly young individuals, as they are expected to have a long follow-up.

Fecal Calprotectin Is Highly Effective to Detect Endoscopic Ulcerations in Crohn's Disease Regardless of Disease Location

BACKGROUND

As the reliability of fecal calprotectin (Fcal) remains debatable to detect endoscopic ulcerations in patients with pure ileal Crohn's disease (CD), we aimed to compare its performances with those observed in patients with colonic or ileocolonic location.

METHODS

Using a prospectively maintained database, we analyzed 123 CD patients with Fcal measurement and ileocolonoscopy performed within 1 month with no therapeutic intervention during this interval. Receiver operating characterstic curves (ROC) were used to determine the best Fcal threshold to detect endoscopic ulcerations, taking into account the clinical relevance and usual recommended indices. Sensitivity, specificity, and positive (PPV) and negative predictive values (NPV) were presented with 95% confidence intervals.

RESULTS

The mean Fcal level was significantly higher in patients with endoscopic ulcerations in the L1 group (P = 0.025) and the L2-L3 group (P < 0.001). Using ROC curves, Fcal >200 µg/g and Fcal >250 µg/g were the best thresholds to detect endoscopic ulcerations in the L1 group (sensitivity = 75.0, 95% CI, 47.6-92.7; specificity = 87.5, 95% CI, 67.6-97.3; PPV = 80.0, 95% CI, 51.9-95.7; and NPV = 84.0; 95% CI, 63.9-95.5) and in the L2-L3 group (sensitivity = 84.1 95% CI, 69.9-93.4; specificity = 74.4, 95% CI, 57.9-87.0; PPV = 78.7, 95% CI, 64.3-89.3, and NPV = 80.6, 95% CI, 64.0-91.8), respectively. We compared the AUC between L1 and L2-L3 groups, and no difference was shown (0.89 vs 0.84, respectively, P = 0.46). We also compared 2-by-2 sensitivity, specificity, PPV, NPV, and accuracy and we did not observe any significant difference.

CONCLUSION

Fecal calprotectin is highly effective to detect endoscopic ulcerations regardless of CD location but requires a lower cutoff value in patients with pure ileal involvement.

Elevated fecal calprotectin and lactoferrin associated with small intestinal lesions in patients with Behçet disease

BACKGROUND AND AIMS

Small intestinal lesions in patients with Behçet disease (BD) have a risk of perforation and hemorrhage requiring surgery. However, no screening strategy for such lesions has been established. We investigated small intestinal lesions in BD patients with video capsule endoscopy (VCE) and analyzed clinical characteristics to identify noninvasive biomarkers of such lesions.

METHODS

This study included 33 BD patients who underwent VCE (PillCam® SB3) at our institution from June 2016 to January 2019. Clinical characteristics, including age, sex, disease duration, body mass index, gastrointestinal symptoms, eye involvement, and blood examinations, were obtained from the medical records of 27 of the 33 patients. Fecal immunochemical tests for hemoglobin, fecal calprotectin (FC), and fecal lactoferrin (FL) were measured. VCE findings of 145 healthy Japanese individuals from a previous report were used as controls.

RESULTS

Two intestinal BD patients were included in the 27 patients. We observed that BD patients exhibit more small intestinal lesions compared with healthy individuals, including erosions, ulcers, and total lesions (erosions or ulcers). FC and FL levels were significantly higher in patients with versus without small intestinal lesions (P = 0.034 and P = 0.046, respectively). Receiver operating characteristic analyses demonstrated that FC (cutoff value = 119 μg/g) and FL (cutoff value = 17 μg/g) were biomarkers for small intestinal lesions in patients with BD.

CONCLUSION

The present study using VCE showed that patients with BD had more small intestinal lesions than healthy individuals. FC and FL could be useful for screening BD patients who may have small intestinal lesions.

Is fecal calprotectin an accurate marker in the management of Crohn's disease?

Although lacking validated cutoff values, fecal calprotectin (FC), besides C-reactive protein, is considered the standard test for assessing disease activity in Crohn's disease (CD). The aim of the present review is to provide a general overview of the literature addressing the role of FC in the clinical and endoscopic assessment of disease activity in CD, seeking correlations with capsule endoscopy, response to therapy, prediction of relapse, and postoperative recurrence. A systematic search of the literature up to September 2019 was performed using Medline, Embase, and the Cochrane Library. Only papers written in English concerning FC in adult patients affected by CD were included. Pediatric studies, in vitro studies, animal studies, studies on blood/serum samples, and studies analyzing FC in ulcerative colitis or in both CD and ulcerative colitis were excluded. Out of 713 citations, 65 eligible studies were identified. FC showed high accuracy in the assessment of intestinal inflammation and response to therapy, in particular in colonic disease, thus proving a good surrogate marker for these aims. FC is useful in identifying patients at high risk for endoscopic relapse or postoperative recurrence, for optimizing or downstage therapy. Unfortunately, FC performs less well in small bowel CD. FC is an effective fecal marker in the management of CD patients, optimizing the use of endoscopic procedures. Owing to its diagnostic accuracy, FC may represent a cornerstone of the "treat-to-target" management strategy of CD patients.

Update on C-reactive protein and fecal calprotectin: are they accurate measures of disease activity in Crohn's disease?

'Treat-to-target' paradigms in Crohn's disease (CD) directed at suppressing intestinal inflammation require accurate and reliable measures of disease activity. Although endoscopy has traditionally been considered a gold standard, cost, complexity, resource limitations, and invasiveness are important limitations. Hence, substantial interest exists for non-invasive serum and fecal biomarkers, namely C-reactive protein (CRP) and fecal calprotectin (FC), in the diagnosis, monitoring, and treatment of CD. Areas covered: We review the evidence for using serum CRP and FC in distinguishing patients with CD from those with irritable bowel syndrome, categorizing disease activity among patients with an established diagnosis of CD, predicting the likelihood of treatment response, identifying asymptomatic patients in medically or surgically induced remission who are at risk for disease relapse, and as treatment targets. Expert commentary: Accurate interpretation of CRP and FC is dependent on several factors including the clinical context, the performance characteristics of the assay, the specified test cut-offs, and the pre-test probability of disease. Emerging evidence indicates that CRP and FC are valuable adjuncts for the management of CD in specific circumstances described in this review.

Low fecal calprotectin predicts clinical remission in Crohn's disease patients: the simple answer to a challenging question

BACKGROUND AND AIM

Fecal calprotectin (FC) is a noninvasive marker of intestinal inflammation. Predicting relapses in Crohn's disease (CD) patients can allow earlier changes in therapy. The aim of this study was to evaluate the role of FC in predicting relapse in CD patients in clinical remission within six months follow-up.

METHODS

Patients with CD who were in clinical remission at least ≥3 months were included in this study. The first FC sample during the remission period was evaluated and was used as the baseline value. Relapse was defined as an unexpected escalation in therapy, hospitalization or need for surgery for active CD. The accuracy and optimal cutoff FC values for predicting clinical relapse at six months were assessed by the area under the ROC curve (AUC).

RESULTS

One hundred and forty-four patients were evaluated, with mean age of 38.4 years. Of these, 13 (9%) had a relapse during the follow-up period. The mean FC value was significantly lower for non-relapsers (203.2 μg/g) than for relapsers (871.3 μg/g), p < .001. The AUC for predicting relapse by using FC values was 0.924. The optimal cutoff FC value to predict relapse was 327 μg/g; with values of sensitivity, specificity, negative predictive value and positive predictive value were 92.3%, 82.4%, 99.1% and 34.3%, respectively.

CONCLUSIONS

FC is more useful in predicting remission maintenance than relapse in patients with CD in clinical remission. Values of FC ≤327 μg/g can exclude relapse at least at six months follow-up period.