Recommendations for pharmacological clinical trials in children with functional constipation: The Rome foundation pediatric subcommittee on clinical trials

BACKGROUND

Evidence for the efficacy of commonly used drugs in the treatment of childhood functional constipation (FC) is scarce, studies are often of low quality and study designs are heterogeneous. Thus, recommendations for the design of clinical trials in childhood FC are needed.

PURPOSE

Members of the Rome Foundation and a member of the Pediatric Committee of the European Medicines Agency formed a committee to create recommendations for the design of clinical trials in children with FC.

KEY RECOMMENDATIONS

This committee recommends conducting randomized, double-blind, placebo-controlled, parallel-group clinical trials to assess the efficacy of new drugs for the treatment of childhood FC. Pediatric study participants should be included based on fulfilling the Rome IV criteria for FC. A treatment free run-in period for baseline assessment is recommended. The trial duration should be at least 8 weeks. Treatment success is defined as no longer meeting the Rome IV criteria for FC. Stool consistency should be reported based on the Bristol Stool Scale. Endpoints of drug efficacy need to be tailored to the developmental age of the patient population.

The role of rectal chloride secretion in childhood constipation

BACKGROUND

Disturbance in fluid secretion, driven by chloride secretion, might play a role in constipation. However, disturbed chloride secretion in those patients has yet to be evaluated. Therefore, the aim of this study was to compare chloride secretion in rectal biopsies of children with functional constipation (FC) to those without constipation.

METHODS

To measure changes in short circuit current (I(sc) in μA cm(-2)) reflecting chloride secretion, intestinal biopsies from children with constipation, to either exclude or diagnose Hirschsprung's disease, and from children without constipation (controls) undergoing colonoscopy for screening of familial adenomatous polyposis, juvenile polyps or inflammatory bowel disease (IBD), were compared and studied in Ussing chambers. Following electrogenic sodium absorption blockade by amiloride, chloride secretory responses to calcium-linked (histamine, carbachol) and cAMP-linked (IBMX/forskolin) secretagogues were assessed.

KEY RESULTS

Ninety-six patients (46 FC) participated; nine FC patients (n = 1 congenital syndrome and n = 8 technical problems) and 13 controls (n = 6 IBD; n = 7 technical problems) were excluded. No significant difference was found in mean (±SE) basal chloride currents between children with FC and controls (9.6 ± 1.1 vs 9.2 ± 0.8; P = 0.75, respectively). Responses to calcium-linked chloride secretagogues (histamine and carbachol) were significantly higher in controls (33.0 ± 3.0 vs 24.5 ± 2.3; P = 0.03 and 33.6 ± 3.4 vs 26.4 ± 2.7; P = 0.05 following histamine and carbachol, respectively).

CONCLUSIONS & INFERENCES

Calcium-linked chloride secretion is disturbed in children with FC. Whether this defect occurs at the level of histamine receptors, components of receptor-linked signal transduction pathways or basolateral Ca(2+) -sensitive K(+) channels enhancing the electrical driving force for apical chloride secretion, remains to be explored.

[Better medicines for children: European measures]

The Paediatric Regulation has been in force in the EU since 1 July 2007. This has changed the procedure for obtaining marketing authorisation of medicines in Europe so that new medications can be adapted safely for use in children. Additional provisions have been made for the use of authorised and generic medications in children. Research is being stimulated through subsidies and the extension of exclusive distribution rights for manufacturers. Other initiatives are aimed at making existing data on the use of medications in children accessible. Many of these tasks are the responsibility of a special European paediatric committee, which also assesses proposals for research on medication use in children.

Long-term results of boerema anterior gastropexy in children

OBJECTIVES

To analyze the long-term results of Boerema anterior gastropexy using the Visick grading system in a university teaching hospital.

METHODS

Retrospective review of 247 children with severe or complicated gastroesophageal reflux disease (GERD). Patients who underwent primary gastropexy between 1990 and 2001 were divided in 3 groups: (A) neurologic impaired patients (n = 83); (B) esophageal atresia patients (n = 36); and (C) patients without underlying disease (n = 128). The median length of follow-up after gastropexy was 7 years and 8 months (range, 1.5-13 years). Follow-up was carried out using a standardized questionnaire and was obtained by telephone. Postoperative recurrence of symptoms during follow-up was considered as failure of the operation.

RESULTS

Postoperative complications occurred in 20 patients (24%) in group A, in 13 patients (36%) in group B and in 23 patients (18%) in group C. Thirty-three patients died during the follow-up period, 5 of whom during the postoperative period. Six children could not be traced; thus, 208 were available for long-term follow-up. Postoperative failures occurred in 12 patients (23%) in group A, in 11 patients (31%) in group B and in 17 patients in group C (14%). Reoperation for recurrence of symptoms due to GERD was performed in 6 patients in group A, in 7 patients in group B and in 2 patients in group C. The final outcome at the time of interview was successful in 81% of group A, in 88% of group B and in 91% of group C.

CONCLUSIONS

In the long term, Boerema anterior gastropexy is an effective operation for complicated GERD in children without underlying disease as well as in neurologically impaired children and patients with esophageal atresia.

Assessment of the rectoanal inhibitory reflex in preterm infants with delayed meconium passage

BACKGROUND

There is an inverse relationship between gestational age, birth weight and the time of first neonatal bowel movement. The authors hypothesized that delayed passage of meconium might result from a delayed maturation of the recto-anal inhibitory reflex (RAIR) in premature infants.

OBJECTIVE

To evaluate whether the RAIR is absent in very preterm infants 28-32 weeks postmenstrual age with delayed meconium production.

STUDY DESIGN

Anorectal manometry was performed in 10 preterm infants (seven male) with delayed meconium production (no meconium in the first 48 hours). Median postmenstrual age was 30 weeks (28-31 weeks). Birth weight ranged from 780 to 1930 g (median, 1395 g). A micromanometric assembly (outer diameter, 2.0 mm) was used which incorporated a 1.5-cm-long sleeve sensor for measurement of resting anal sphincter pressure and relaxation. Four side-holes recorded anal and rectal pressures. Rectal distension was performed with direct air insufflation to elicit the RAIR.

RESULTS

The time from birth to passage of meconium ranged from 48 to 105 hours (median, 82 hours). The mean anal sphincter pressure, rectal pressure, and anal sphincter oscillation frequency were 22.0 +/- 5.0 mm Hg, 6.9 +/- 2.0 mm Hg, and 9.8 +/- 1.9/min, respectively. A normal RAIR was elicited in all infants.

CONCLUSION

Anorectal manometry recordings in premature infants with delayed passage of meconium showed normal anorectal pressures and a normal RAIR, suggesting that delayed meconium passage is not related to the absence of a RAIR.

Prognosis of constipation: clinical factors and colonic transit time

BACKGROUND

Measurement of colonic transit time (CTT) is sometimes used in the evaluation of patients with chronic constipation.

AIM

To investigate the relation between symptoms and CTT, and to assess the importance of symptoms and CTT in predicting outcome.

METHODS

Between 1995 and 2000, 169 consecutive patients (median age 8.4 years, 65% boys) fulfilling the criteria for constipation were enrolled. During the intervention and follow up period, all kept a diary to record symptoms. CTT was measured at entry to the study.

RESULTS

At entry, defecation frequency was lower in girls than in boys, while the frequency of encopresis episodes was higher in boys. CTT values were significantly higher in those with a low defecation frequency (< or =1/week) and a high frequency of encopresis (> or =2/day). However, 50% had CTT values within the normal range. Successful outcome occurred more often in those with a rectal impaction. CTT results <100 hours were not predictive of outcome. However, those with CTT >100 hours were less likely to have had a successful outcome.

CONCLUSION

The presence of a rectal impaction at presentation is associated with a better outcome at one year. A CTT >100 hours is associated with a poor outcome at one year.

The incidence of pediatric inflammatory bowel disease in the Netherlands: 1999-2001

BACKGROUND

The incidence of inflammatory bowel disease (IBD) seems to be rising. Incidence studies could provide more insight into geographical differences and thereby lead to the identification of etiological factors. The aim of this study was to prospectively assess the incidence of pediatric IBD in the Netherlands from 1999 to 2001, using both an active physician case-reporting registry and a nationwide pathology database.

METHODS

All pediatricians in the Netherlands were sent monthly identification cards to be returned if they had diagnosed a new case of IBD in a pediatric patient. Follow-up questionnaires were sent to physicians reporting new cases of IBD. The pathology database contains reports from all cytologic and histologic diagnoses made in the Netherlands. Two independent raters searched the database for new IBD cases. Cases identified from the pathology database were labeled as "probable IBD" and "possible IBD." Cases were cross-checked across databases on the basis of gender, date of birth, date of biopsy, and place of residence. Age-specific incidence rates were calculated for the Dutch population for the year 2000.

RESULTS

Five hundred forty-six probable cases of IBD were identified; 217 cases were labeled as possible. The incidence rate was 5.2 new cases per 100000 children (<18 years) per year. An increase in incidence with age was observed. Only 24% of the cases were ascertained through the clinical registry.

CONCLUSION

The incidence of IBD cases in the Netherlands is comparable with that reported in other European countries. Epidemiological studies using case reporting by physicians may be underestimates of true incidence rates.

Severity of enterocolitis is predicted by IL-8 in paediatric oncology patients

Enterocolitis in oncology patients remains an important complication, but there is a lack of insight into its likely severity from microbial, pathological and inflammatory aspects. Paediatric oncology patients admitted with neutropenic fever, who developed abdominal pain and diarrhoea, were monitored by the takers of rectal biopsies, cultures, and inflammatory marker measurements. Twenty-five patients were included (mean age 7.1 years). 8 patients (32%) needed intensive care treatment, 3 (12%) patients died. Gram-positive bacteraemia was diagnosed in 4 patients (16%). Most patients had negative blood and stool cultures. Predictors of a severe clinical course of the enterocolitis were an increased serum interleukin-8 (IL-8) (>1000 pg/ml) level and an increased serum C-reactive protein level (CRP) (>150 mg/l) level, both measured on the first day of clinical illness. Relative risks (RR) for admission to an Intensive Care Unit (ICU) were 11.3 (95% Confidence Interval (CI) 1.6-77.9) for elevated IL-8 levels and 6.4 (95% (CI) 0.92-45.1) for increased CRP levels. Rectal biopsies and pathology could not predict outcome (P=0.22). IL-8 analysis at the onset of enterocolitis symptoms can identify high-risk patients, which might be used clinically to design future intervention trials.

Maturation of the rectoanal inhibitory reflex in very premature infants

OBJECTIVE

To characterize anal sphincter function in very premature infants < or =30 weeks' postmenstrual age (PMA) and to evaluate the time of maturation of the rectoanal inhibitory reflex (RAIR) by using a sleeve catheter.

STUDY DESIGN

Anorectal manometry was performed in 16 healthy neonates (nine girls) with a mean PMA of 29 weeks (range, 27-30 weeks) and a birth weight of 640 to 1590 g (median, 1220 g) with a micromanometric assembly (outer diameter, 2.0 mm). The assembly incorporated a 1.5-cm-long sleeve sensor for measurement of resting anal sphincter pressures and relaxation, and four side holes recorded anal and rectal pressures. Rectal distention was performed with direct air insufflation to elicit the RAIR.

RESULTS

The mean anal sphincter pressure, rectal pressure, and anal sphincter oscillation frequency were 24.5+/-11.4 mm Hg, 6.5+/-4.8 mm Hg, and 11.1+/-2.3/min, respectively. A normal RAIR could be elicited in 13 (81%) infants studied. In two infants, the RAIR could not be elicited because of a low anal sphincter pressure of only 5 mm Hg. In the other child, no RAIR was seen despite the repeated insufflation of at least 5 mL of air.

CONCLUSION

The majority (81%) of premature infants older than 26 weeks' PMA have normal anorectal pressures and a normal RAIR.

Pseudomembranous and neutropenic enterocolitis in pediatric oncology patients

Neutropenic enterocolitis in oncological patients represents a wide spectrum of clinicopathological pictures each with its own entity. Early diagnosis of enterocolitis can lead to improved supportive care and therefore better outcome. We present two cases--patient A, a child with pseudomembranous colitis caused by Clostridium difficile, and patient B, a child with neutropenic enterocolitis, where no organism was found. By allowing an insight into the pathology, immunology and culture results, we demonstrated that early diagnosis leads to improved management and therefore improved outcome.

[Infliximab therapy in children and adolescents with refractory Crohn's disease in the Netherlands; experience with 23 patients]

OBJECTIVE

To describe the clinical experience of infliximab treatment in children and adolescents with refractory Crohn's disease in the Netherlands.

DESIGN

Descriptive.

METHOD

From November 1998 to February 2002, 23 patients (aged 7-18 years) with refractory Crohn's disease or steroid-dependent Crohn's disease (with or without severe fistulas) were treated with infliximab. Patients were treated with 1-11 infusions, with an average follow-up of 14.5 months after the start of infliximab therapy.

RESULTS

Ten patients had refractory Crohn's disease. Four of these showed good long-term response on infliximab treatment (modified 'Paediatric Crohn's disease activity index' (PCDAI) < or = 10 points or growth acceleration after stunting). Twelve patients had Crohn's disease with severe fistulas. Five of these showed good long-term response (closure or non-productiveness of fistulas). One patient had metastatic Crohn's disease in the skin and showed good long-term response.

CONCLUSION

Response rates were lower than observed in previous studies. Specifically, a decrease of response was demonstrated after repeated infusion. The treatment frequency should be determined by the increase in complaints rather than using a fixed interval of 8 weeks.

[Microvillus inclusion disease, a rare cause of severe congenital diarrhea]

To date, microvillus inclusion disease (MID) has been diagnosed in six Dutch patients. It is a rare autosomal recessive hereditary intestinal disorder mostly presenting with malabsorption and severe secretory diarrhoea from birth. The diagnosis is confirmed by electron microscopy of intestinal mucosal biopsies, which show characteristic intracytoplasmic vesicles containing clearly recognisable microvilli and irregularly distributed microvilli in the brush border. The two clinical forms of the disease that have been recognised internationally, a 'congenital' and a 'late-onset' form of MID, have also been observed in the Dutch patients. At the last follow-up five patients had died, the sixth was 17 years old and alive. The pathogenesis and genetics of MID are, as yet, unknown. Eventually, all patients die from complications of the disease, notably from the total parenteral nutrition. The only chance of survival is intestinal or combined liver-intestinal transplantation.

Water absorption enhances the uptake of mannitol and decreases Cr-EDTA/mannitol permeability ratios in cat small intestine in situ

BACKGROUND

Recently, we hypothesized that mannitol absorption in human intestinal permeability tests is a reflection of small intestinal water absorption and is dependent mainly on the efficiency of the countercurrent multiplier in the villi. This may affect the outcome of clinical double-sugar permeability tests. We tested the hypothesis in cats, another species with an efficient countercurrent multiplier.

METHODS

The lumen-to-tissue transport of [14C]mannitol and [51Cr]EDTA was studied in in situ perfused jejunum of eight anaesthetized cats using four isotonic perfusion solutions with varying sodium and glucose content. The transport of water was monitored, and the absorption rate of the probes was calculated by their disappearance from the perfusate.

RESULTS

There was a significant positive correlation between water absorption and [14C]mannitol clearance from the different perfusates (r = 0.99; P < 0.01), whereas this correlation was absent for [51Cr]EDTA clearance (r = 0.05; P = 0.95). There was also a significant negative correlation between water absorption and [51Cr]EDTA/[14C]mannitol clearance ratios (r = 0.98; P < 0.02).

CONCLUSIONS

The results show a prominent effect of water absorption on mannitol uptake through pores which, also during glucose transport, exclude Cr-EDTA. The difference in water absorption from the solutions used in cat small intestine is dependent on the effectiveness of the countercurrent multiplier; we conclude that the capability of this mechanism influences mannitol absorption in vivo. Qualitatively comparable results were obtained using oral test solutions with varying NaCl and glucose concentrations in human volunteers. We propose that the functioning of the countercurrent multiplier is essential for the interpretation of double-sugar tests in clinical studies.