Fecal lactoferrin: a noninvasive fecal biomarker for the diagnosis and surveillance of pouchitis

Sensitivity and specificity of diagnostic modalities in pouchitis: a systematic review and meta-analysis

Restorative proctocolectomy (RPC) is the most common surgical procedure to restore gastrointestinal continuity after surgical resection of the colon and rectum. Pouchitis is a common complication with several different modalities that can be used to aid diagnosis. This systematic review and meta-analysis aimed at exploring the sensitivity and specificity these diagnostic modalities. The medical literature was searched using MEDLINE, EMBASE and EMBASE classic and PubMed from 1978 to June 2022. We calculated descriptive statistics using sensitivity, specificity, and false-positive rate of the primary studies and also their positive and negative likelihood ratios, and their diagnostic odds ratios. The screen found 5477 records with 13 studies being included. Faecal lactoferrin was found to have the highest pooled sensitivity and specificity of 98% and 88% respectively with imaging modalities coming in second and faecal calprotectin third with pooled sensitivities and specificities of 87% and 79% and 74% and 81% respectively. Faecal biomarkers particularly lactoferrin and imaging modalities may have an important role to play in diagnosing pouchitis. Importantly due to delays in availability of pouchoscopy, our data supports early ordering of these tests to help delineate from other causes. Further studies are required with larger cohort sizes to further validate these tests.

Disease Monitoring of the Ileoanal Pouch: How to Utilize Biomarkers, Imaging, and Pouchoscopy

PURPOSE OF REVIEW

Restorative proctocolectomy with ileal pouch-anal anastomosis for ulcerative colitis has been associated with multiple short- and long-term complications. In this review, we examine the role of biomarkers, imaging, and pouchoscopy in the assessment of patients after ileal pouch-anal anastomosis, with a particular focus on the emergence of novel biomarkers and techniques for evaluating and risk stratifying patients after this procedure in the hopes of improving outcomes in this specific population.

RECENT FINDINGS

There are indications that that the incidence of pouchitis may be increasing in recent decades. Calprotectin and other non-invasive imaging tests such as ultrasound may offer advantages in distinguishing patients with inflammatory conditions of the pouch from other etiologies. In the search for other biomarkers that may identify patients at risk for inflammatory conditions of the pouch, the stool microbiota and metabolomics may play a key role in identifying those patients at greatest risk for complications. Advances in biomarkers, imaging, and standardized pouchoscopy scoring offer immediate improvements in clinical care and will prompt future research efforts.

Biomarkers for the Evaluation of Pouch Inflammation: A Systematic Review

Background

Ileal pouch inflammation is a common problem following ileal pouch-anal anastomosis (IPAA). Despite its prevalence, diagnosis remains multimodal and requires endoscopy. The use of biomarkers in the prediction of and/or association with pouchitis has not been well characterized. We performed a systematic review to summarize the available evidence.

Method

A search of Ovid, MEDLINE, Cochrane Library, EMBASE, and Web of Science was conducted. Inclusion criteria included studies evaluating biomarkers for the evaluation and prediction of inflammation in patients with IPAA utilizing pouchoscopy as the gold standard. Exclusion criteria included studies on the role of the microbiome or genetic markers.

Results

A total of 28 studies, 5 case-control studies, and 23 observational cohort studies were identified. Fecal biomarkers were assessed in 23 studies, of which fecal calprotectin was the most commonly studied with sensitivities ranging from 57% to 92% and specificities from 19% to 92%. Six studies examined serum biomarkers. None of the serum biomarkers demonstrated a high sensitivity or specificity in association with pouch inflammation. Six studies described the longitudinal assessment of biomarkers. Of these studies, only three reported a predictive role of biomarkers in diagnosing endoscopic inflammation.

Conclusions

Biomarkers have emerged as a potential option to improve the management of pouchitis given the relative ease of sampling compared to pouchoscopy. Unfortunately, the evaluated biomarkers have not consistently demonstrated accuracy in predicting inflammation. Moreover, these biomarkers have not been reliably shown to be sensitive or specific in association with endoscopic pouch inflammation to merit their widespread use in clinical practice.

Non-invasive Monitoring of Pouchitis After Total Proctocolectomy Using Fecal Calprotectin Levels

BACKGROUND

Fecal calprotectin (FC) is the most widely used marker for evaluating the disease activity of ulcerative colitis (UC). However, studies on FC in pouchitis after total proctocolectomy are scarce. We aimed to examine the correlations between the FC level and clinical findings and Pouchitis Disease Activity Index (PDAI) in UC patients who underwent total proctocolectomy (TP) with ileal pouch-anal canal anastomosis (IPAA) or ileal pouch-anal canal anastomosis (IACA).

METHODS

Between April 2008 and March 2018, 15 patients, consisting of 8 males and 7 females, with an average age at operation of 46.5 years, participated in this study. The average observation period was 68.3 months. The subjects underwent FC level measurements and endoscopic examinations.

RESULTS

The mean FC level was 418.69 μg/g (range: 10-1650 μg/g). Pouchitis was found in one (6.6%) patient, as detected by endoscopy. Among the 15 cases, FC levels were positively correlated with white blood cell count as well as albumin and C-reactive protein levels. There was a significant positive correlation between the PDAI score and FC levels (p<0.05). The median FC level was 111 mg/g in those with pouchitis, which was significantly higher than the 16 mg/g in those without pouchitis (p<0.05). Moreover, a significant positive correlation was found between the endoscopic findings of inflammation and FC levels (p<0.00005).

CONCLUSION

FC levels were correlated with the PDAI score, blood testing data, and endoscopic findings, suggesting that the FC level could be a useful index of postoperative pouchitis and ileal pouch condition in patients undergoing TP with IPAA as UC treatment.

Disease Activity Indices for Pouchitis: A Systematic Review

BACKGROUND

Several indices exist to measure pouchitis disease activity; however, none are fully validated. As an initial step toward creating a validated instrument, we identified pouchitis disease activity indices, examined their operating properties, and assessed their value as outcome measures in clinical trials.

METHODS

Electronic databases were searched to identify randomized controlled trials including indices that evaluated clinical, endoscopic, or histologic pouchitis disease activity. A second search identified studies that assessed the operating properties of pouchitis indices.

RESULTS

Eighteen randomized controlled trials utilizing 4 composite pouchitis disease activity indices were identified. The Pouchitis Disease Activity Index (PDAI) was most commonly used (12 of 18; 66.7%) to define both trial eligibility (8 of 12; 66.7%), and outcome measures (12 of 12; 100%). In a separate search, 21 studies evaluated the operating properties of 3 pouchitis indices; 90.5% (19 of 21) evaluated validity, of which 42.1% (8 of 19) evaluated the construct validity of the PDAI. Criterion validity (73.7%; 14 of 19) was evaluated through correlation of the PDAI with fecal calprotectin (FCP; r = 0.188 to 0.71), fecal lactoferrin (r = 0.570 to 0.582), and C-reactive protein (CRP; r = 0.584). Two studies assessed correlation of the modified PDAI (mPDAI) with FCP (r = 0.476 and r = 0.565, respectively). Fair to moderate inter-rater reliability of the PDAI (k = 0.440) and mPDAI (k = 0.389) was reported in a single study. Responsiveness of the PDAI pre-antibiotic and postantibiotic treatment was partially evaluated in a single study of 12 patients.

CONCLUSIONS

Development and validation of a specific pouchitis disease activity index is needed given that existing instruments are not valid, reliable, or responsive.

The role of fecal calprotectin in the diagnosis of acute pouchitis following IPAA for ulcerative colitis: a systematic clinical review

PURPOSE

Total proctocolectomy (TPC) with ileal pouch anal anastomosis (IPAA) is commonly performed for patients with refractory ulcerative colitis (UC). Pouchitis occurs in 20-50% of these patients. Fecal calprotectin is a biomarker that correlates well with the pouchitis disease activity index. However, its role in the diagnosis and management of acute pouchitis has not been thoroughly defined. The aim of this study is to review previously established cut-off values and contextualize the clinical utility of fecal calprotectin.

METHODS

Search of Medline, EMBASE, CENTRAL, and PubMed was performed. Articles were eligible if they measured fecal calprotectin in the setting of pouchitis in patients who underwent TPC with IPAA for UC. Risk of bias of the included studies was evaluated with the QUADAS-2.

RESULTS

From 117 relevant citations, seven studies with 256 patients (44.8% female, 39.88 years) met inclusion criteria. The pooled prevalence of pouchitis was 42%. The derived fecal calprotectin cut-off values ranged from 56 to 494 μg/g. The corresponding sensitivities and specificities ranged from 57 to 100% and 38 to 92%, respectively. The area under the curve was reported in three studies and ranged from 0.832 to 0.840.

CONCLUSION

Fecal calprotectin may be a reliable diagnostic tool for acute pouchitis in patients following TPC with IPAA for UC. The high sensitivity of fecal calprotectin for detection of pouchitis makes it a valuable test for ruling out pouchitis. When used in conjunction with other biomarkers, the high specificity offers value in ruling in pouchitis. However, given the complexity of this disease process, relying solely on biomarkers for diagnosis is currently unreasonable.

Disease and Treatment Patterns Among Patients With Pouch-related Conditions in a Cohort of Large Tertiary Care Inflammatory Bowel Disease Centers in the United States

BACKGROUND

Gaps exist in our understanding of the clinical course of pouch-related disorders.

METHODS

We evaluated baseline disease activity and longitudinal treatment patterns among patients with inflammatory conditions of the pouch.

RESULTS

Among 468 patients with an ileal pouch-anal anastomosis (IPAA), 94 (20%) had acute pouchitis, 96 (21%) had chronic pouchitis, and 192 (41%) had Crohn disease of the pouch. Following an IPAA, 38% of patients were treated with a biologic and 11% underwent inflammatory bowel disease- or bowel-related surgery.

CONCLUSIONS

Treatment patterns after IPAA indicate that pouch-related disorders have a significant impact on individual patients and the healthcare system.

Consecutive Monitoring of Fecal Calprotectin and Lactoferrin for the Early Diagnosis and Prediction of Pouchitis after Restorative Proctocolectomy for Ulcerative Colitis

OBJECTIVES

This prospective study was conducted to evaluate the significance of consecutive monitoring of fecal calprotectin and lactoferrin for the early diagnosis and prediction of pouchitis after restorative proctocolectomy for ulcerative colitis (UC).

METHODS

Sixty patients who had ileostomy closure following total proctocolectomy and ileal pouch-anal anastomosis for UC were included. Stool samples were collected for the measurement of calprotectin and lactoferrin every 2 months up to 12 months after the ileostomy closure. When patients had symptoms suggestive of pouchitis, endoscopic examination was immediately undertaken. All asymptomatic patients underwent endoscopy at 12 months. Pouchitis was defined as a pouchitis disease activity index score of ≥7.

RESULTS

During the 12 months, 10 patients (17%) developed pouchitis. In patients with pouchitis, fecal calprotectin and lactoferrin levels were elevated already 2 months before the diagnosis of pouchitis. In contrast, these fecal biomarkers remained at low levels, and they did not change significantly in patients without pouchitis. A cutoff value of 56 μg/g for calprotectin had a sensitivity of 100% and a specificity of 84% to predict pouchitis, whereas a cutoff value of 50 μg/g for lactoferrin had a sensitivity of 90% and a specificity of 86%. At the time of endoscopy, the median calprotectin and lactoferrin levels were significantly higher in patients with pouchitis than those without pouchitis.

CONCLUSIONS

Elevated fecal calprotectin and lactoferrin levels appeared to be significant predictors of pouchitis after restorative proctocolectomy for UC. Consecutive monitoring of these fecal biomarkers is useful for the early diagnosis of pouchitis.

Serum alpha-1 antitrypsin: a noninvasive marker of pouchitis

BACKGROUND

Patients with ulcerative colitis undergoing total proctocolectomy with ileal pouch-anal anastomosis may develop pouchitis. Alpha-1-antitrypsin (AAT) is an acute phase reactant produced mainly by hepatocytes, but also locally in the gut. Data on noninvasive biomarkers of pouchitis are scarce.

METHODS

To identify biomarkers that correlate with pouch inflammation, ulcerative colitis pouch patients were prospectively recruited and underwent clinical, endoscopic, and histologic evaluations. The Pouchitis Disease Activity Index (PDAI) was calculated, and pouchitis was defined by a score ≥7. Serum and fecal AAT, C-reactive protein (CRP), fecal calprotectin, ferritin and albumin levels were measured.

RESULTS

Seventy-one ulcerative colitis pouch patients (mean age 43.8 ± 8.3 yr, 50.7% males) were included. The main indication for ileal pouch-anal anastomosis was intractable colitis (83.1%). Median serum AAT level (183.0 mg/dL, 155.1-232.0) was significantly higher in patients with a PDAI ≥7 compared with those with a PDAI <7 (167.6 mg/dL, 151.0-181.0) (P = 0.03). Serum AAT, CRP, and fecal calprotectin levels significantly correlated with PDAI scores: r = 0.583, P < 0.001; r = 0.584, P < 0.001; and r = 0.606, P = 0.001, respectively. Serum AAT and CRP levels correlated significantly (r = 0.650, P < 0.001), as did serum AAT and fecal calprotectin levels (r = 0.663, P < 0.001). Fecal AAT levels did not correlate with any tested biomarker. Receiver operating characteristic analysis demonstrated sensitivity, specificity, and positive predictive value of 55.6%, 100%, and 100%, respectively, for diagnosing pouchitis at a serum AAT cutoff level of 189 mg/dL.

CONCLUSIONS

Serum AAT is a specific noninvasive biomarker of pouchitis. AAT levels correlate with disease activity and CRP and calprotectin levels.

Update on the pathogenesis and management of pouchitis

Pouchitis is an inflammatory complication after restorative proctocolectomy and ileal pouch-anal anastomosis (IPAA). IPAA is the surgical treatment of choice in patients with ulcerative colitis (UC) who require colectomy. Initial episodes of acute pouchitis generally respond to antibiotics but significant numbers of cases eventually become dependent on or refractory to antibiotics. Management of chronic antibiotic refractory pouchitis is challenging and can ultimately lead to pouch failure. The etiopathogenesis is unknown though recent studies have implicated bacterial dysbiosis of the pouch microbiota, NOD2 polymorphism, and Clostridium difficile infection in the development of severe pouchitis. Early identification of risk factors can help in tailoring therapy and reducing cases of chronic pouchitis.

Clinical utility of fecal biomarkers for the diagnosis and management of inflammatory bowel disease

Diagnosis and monitoring of inflammatory bowel diseases rely on clinical, endoscopic, and radiologic parameters. Inflammatory biomarkers have been investigated as a surrogate marker for endoscopic diagnosis of inflammatory activity. Fecal inflammatory biomarkers such as calprotectin and lactoferrin are direct products of bowel inflammation and provide an accurate and noninvasive diagnostic and monitoring modality for Crohn's disease and ulcerative colitis. This report contains an overview of the currently existing literature pertaining to clinical implications of fecal biomarkers for diagnosis, monitoring, and prediction of outcomes of inflammatory bowel disease.