Clinical trial NCT02197780: Head-to-head Comparison of Two Fecal Biomarkers to Screen Children for IBD
Official title: Calprotectin or Calgranulin C-test Before Undergoing Endoscopy: a Prospective Diagnostic Accuracy Study Comparing Two Fecal Biomarkers for Pediatric IBD
Study type: OBSERVATIONAL
Overall status: COMPLETED
Conditions: Abdominal Pain
Rectal Bloodloss
Diarrhea
Inflammatory Bowel Disease
Crohn's Disease
Ulcerative Colitis
Irritable Bowel Syndrome
Keywords: Diagnostic accuracy
Fecal biomarker
Clinical Decision Rule
Cohort Study
Lead sponsor: University Medical Center Groningen
Sponsor class: OTHER
Collaborators: name: Cisbio Bioassays
First posted: 2014-07-23
Enrollment: 355
Sex: ALL
Minimum age (years): 6
Maximum age (years): 18
Standard ages: CHILD
ADULT
Accepts healthy volunteers: no
Observational model: COHORT
Time perspective: PROSPECTIVE
Sampling method: PROBABILITY_SAMPLE
Study population: Eligible for inclusion are consecutive children and teenagers who consult their pediatrician and have gastro-intestinal symptoms suggestive of IBD. Participating centers are located in the Northern and Southern region of the Netherlands and the Flemish-speaking region of Belgium.

Brief summary: RATIONALE:

A substantial proportion of children and teenagers with suspected inflammatory bowel disease (IBD) referred for endoscopy do not have the disease. The investigators designed a clinical decision rule that included a calprotectin stool test to discern which patients require further investigations. The accuracy of this diagnostic strategy is 88.5% with a low risk of missing IBD cases. Although the number of negative endoscopies was reduced after introduction of this strategy, still 22% of the referred children and teenagers underwent an unnecessary invasive test. S100A12 (calgranulin C) is a cytoplasmic protein secreted exclusively by activated neutrophils and this stool marker may be more IBD-specific than calprotectin.

OBJECTIVE:

To determine whether the specificity of S100A12 is superior to the specificity of calprotectin without sacrificing sensitivity

HYPOTHESIS:

Inclusion of the calgranulin C stool test will improve the specificity of the screening-strategy.

Detailed description: DESIGN:

A prospective diagnostic accuracy study in several outpatient clinics for general paediatrics and several tertiary care hospitals in the Netherlands and Belgium.

STUDY POPULATION:

Eligible for inclusion are consecutive children and teenagers between 6 and 18 years who consult their pediatrician and have gastro-intestinal symptoms suggestive of IBD.

INTERVENTION:

Patients will be managed according to a calprotectin-based-referral strategy. Those with an elevated calprotectin level without colon pathogens are considered to have a high probability of IBD and may require referral for endoscopy (the preferred reference standard). Patients with confirmed gastrointestinal infection are advised to have their stools retested. Patients with normal calprotectin levels are considered to have a low probability of IBD and will therefore have a low change to be subjected to endoscopy. In these patients with low probablity of IBD an alternative reference standard may be performed, being clinical follow-up for 6 months. The decision for endoscopy or clinical follow up is up to the clinician's discretion, based on the combination of all symptoms, physical examination, blood results, fecal markers and colon pathogens.

Next to calprotectin, also S100A12 will be measured in all stool samples. We will perform a post hoc scenario analysis to compare the test characteristics of both fecal markers.

OUTCOME MEASURES:

The primary outcome measure is the difference in specificity between FC and S100A12 among the total number of non-IBD patients.

We adjusted our previously formulated outcome measure, being the proportion of patients with non-inflammatory conditions among the total number of patient subjected to endoscopy, for two reasons.

1. During an interim analysis in August 2016 the proportion of patients subjected to endoscopy was lower as expected (34% instead 46%). To reach the required amount of patients with the reference standard (endoscopy) we needed to extend the study for several months.
2. Triggered by a recently published paper by Naaktgeboren et al in the BMJ, we realized that our initial design would lead to biased results.

Secondary endpoints are the difference in sensitivity among the total number of patients with IBD and the diagnostic accuracy characteristics (sensitivity, specificity, positive predictive value, negative predictive value, area under the curve, best cut-off point) for both markers individually. All diagnostic accuracy characteristics will be calculated with 1) a pre-specified cut-off value based on literature, 2) the best cut-off point calculated with the data from this trial.

POWER/DATA ANALYSIS:

At the start of our trial we defined a sample size calculation, based on the previously described outcome measure including only patients with endoscopy. Based on a previous cohort study we expected that 46% of the recruited patients would undergo endoscopy. Using a sample size calculation based on independent samples calculated with a Fisher's exact test, we calculated that with 154 patients subjected to endoscopy the study would have 80% power to detect a 50% relative reduction of the primary outcome from 22% false positives with FC to 11% false positives with S100A12, at a one-sided alpha level of 0.05. The total number of patients to be recruited for this diagnostic accuracy study was therefore calculated at 335.

In the slipstream of the adjustment of the primary outcome measure, we adjusted our sample size. We now use McNemar's test for paired samples to compare the proportion of concordant and discordant results between FC and S100A12 in all patients with the disease or without the disease.

To calculate the new sample size we used a specificity of FC of 0.70, based on recent individual patient data meta-analysis of Degraeuwe and we expected S100A12 would lead to 50% relative improvement. A sample size of 130 subjects achieves 80% power to detect a difference of 0,15 between the two diagnostic tests whose specificities are 0,70 and 0,85. This procedure uses a two-sided McNemar test with a significance level of 0,05. The prevalence of non-IBD in the population is 0,64. The proportion of discordant pairs is 0,23.

ETHICAL CONSIDERATIONS:

The Medical Ethical Committee of the University Medical Center in Groningen has granted exemption from WMO-approval, as it involves the collection of data generated by routine medical care. After measurement of calprotectin levels and testing for microbial gut pathogens the residual material will be used for the measurement of calgranulin C levels. When patients and their parents give permission, residual feces will be stored for a maximum period of 15 years for future diagnostic research.

TIME SCHEDULE:

Total running time is 30 months, including 6 months to complete the follow up and 2 months for analysis and reporting.

Eligibility criteria: Eligible patients are those aged between 6 and 18 years with at least one of the following criteria:

* Persistent diarrhea (at least 4 wks)
* Recurrent abdominal pain with diarrhea (at least 2 episodes in 6 months)
* Rectal bloodloss
* Peri-anal disease

OR at least two of the following criteria:

* Involuntary weight loss
* First degree family member with IBD
* Anemia (HB \< -2 SD for age and gender)
* Increased marker of inflammation (ESR \>20 mm/hour or CRP \>10 mg/L)
* Extra-intestinal symptoms (erythema nodosum, arthritis, uveitis, thromboembolism, aphtous ulcera)

We did not define any exclusion criteria.

Primary outcomes:
measure: The difference in specificity between FC and S100A12 among the total number of non-IBD patients.
timeFrame: 6 months
Secondary outcomes:
measure: The difference in sensitivity between FC and S100A12 among the total number of IBD patients.
timeFrame: 6 months
measure: Diagnostic test accuracy characteristics for both FC and S100A12
timeFrame: 6 months
Other outcomes:
measure: Scenario analysis with the test accuracy for a combination of FC and S100A12 in (sub)selection of patients.
timeFrame: 6 months
Locations:
city: Antwerpen
country: Belgium
facility: Sint Vincentiusziekenhuis
city: Antwerpen
country: Belgium
facility: University Hospital Antwerpen
city: Gent
country: Belgium
facility: University Hospital Gent
city: Almelo
country: Netherlands
facility: ZGT Almelo
city: Assen
country: Netherlands
facility: Wilhelmina Ziekenhuis
city: Deventer
country: Netherlands
facility: Deventer Ziekenhuis
city: Drachten
country: Netherlands
facility: Ziekenhuis Nij Smellinghe
city: Emmen
country: Netherlands
facility: Scheper Ziekenhuis
city: Enschede
country: Netherlands
facility: Medisch Spectrum Twente
city: Goes
country: Netherlands
facility: Admiraal de Ruyter ziekenhuis
city: Groningen
country: Netherlands
facility: University Medical Center Groningen
city: Groningen
country: Netherlands
facility: Martini Ziekenhuis
city: Heerenveen
country: Netherlands
facility: Tjongerschans
city: Hoogeveen
country: Netherlands
facility: Bethesda Hospital
city: Leeuwarden
country: Netherlands
facility: Medisch Centrum Leeuwarden (MCL)
city: Roosendaal
country: Netherlands
facility: Bravis ziekenhuis
city: Stadskanaal
country: Netherlands
facility: Refaja Ziekenhuis
city: Winschoten
country: Netherlands
facility: Ommelander Ziekenhuis Groep
city: Zwolle
country: Netherlands
facility: Isala Kliniek
Study officials:
affiliation: University Medical Center Groningen
name: Patrick F van Rheenen, MD PhD
role: PRINCIPAL_INVESTIGATOR
References:
citation: Van de Vijver E, Heida A, Ioannou S, Van Biervliet S, Hummel T, Yuksel Z, Gonera-de Jong G, Schulenberg R, Muller Kobold A, Verkade HJ, van Rheenen PF; CACATU CONSORTIUM. Test Strategies to Predict Inflammatory Bowel Disease Among Children With Nonbloody Diarrhea. Pediatrics. 2020 Aug;146(2):e20192235. doi: 10.1542/peds.2019-2235. Epub 2020 Jul 21.
citation: Heida A, Van de Vijver E, van Ravenzwaaij D, Van Biervliet S, Hummel TZ, Yuksel Z, Gonera-de Jong G, Schulenberg R, Muller Kobold A, van Rheenen PF; CACATU consortium. Predicting inflammatory bowel disease in children with abdominal pain and diarrhoea: calgranulin-C versus calprotectin stool tests. Arch Dis Child. 2018 Jun;103(6):565-571. doi: 10.1136/archdischild-2017-314081. Epub 2018 Mar 7.
citation: Heida A, Van de Vijver E, Muller Kobold A, van Rheenen P. Selecting children with suspected inflammatory bowel disease for endoscopy with the calgranulin C or calprotectin stool test: protocol of the CACATU study. BMJ Open. 2017 May 29;7(5):e015636. doi: 10.1136/bmjopen-2016-015636.
citation: Heida A, Dijkstra A, Dantuma SK, van Rheenen PF. A Cross-Sectional Study on the Perceptions and Practices of Teenagers With Inflammatory Bowel Disease About Repeated Stool Sampling. J Adolesc Health. 2016 Oct;59(4):479-81. doi: 10.1016/j.jadohealth.2016.06.009. Epub 2016 Aug 6.