Fecal elastase-1 is superior to fecal chymotrypsin in the assessment of pancreatic involvement in cystic fibrosis

Pancreas and pancreatitis: Exocrine pancreatic insufficiency

Exocrine pancreatic insufficiency (EPI) is highly prevalent among individuals with cystic fibrosis (CF). Individuals diagnosed with EPI are often labeled as having "pancreas insufficient cystic fibrosis (PI-CF)" while those with normal exocrine function are labeled as "pancreas sufficient CF (PS-CF)." This diagnosis of EPI relies on clinical and laboratory features and management involves consumption of pancreas enzyme replacement therapy. In this review, we discuss the nuances of diagnosis and management of EPI in CF. We also present emerging evidence on the effects of CFTR modulating agents on the management of EPI, and speculate that these medications may lead to greater heterogeneity in management of EPI in CF moving forward.

Preanalytical and analytical factors affecting elastase quantitation in stool

Exocrine pancreatic insufficiency (EPI) is a condition caused by a deficiency of exocrine pancreatic enzymes, resulting in malabsorption of nutrients. Clinical manifestations of EPI may include steatorrhea, weight loss, diarrhea, and abdominal pain. Although direct testing is the most sensitive and specific for EPI, these tests are invasive, time consuming, expensive, and not well standardized. Fecal elastase (FE-1) has been shown to be an indirect marker of the exocrine secretory capacity of the pancreas and has become the most commonly employed indirect test for diagnosis of EPI. Measurement of fecal elastase consists of two main phases, a preanalytical phase and analytical phase. The preanalytical phase involves stool collection, storage and handling. The second phase is the analytical phase, which includes the actual assay processes and products used to produce a result. For FE-1 this includes sample extraction and measurement on an immunoassay. Each step in the process can influence the result and contribute to heterogeneity in FE-1 measurement, potentially impacting clinical diagnosis and management. Thus, this paper provides an overview of the preanalytical and analytical factors that can affect measurement and interpretation of FE-1 results.

Management of chronic pancreatitis

Chronic pancreatitis results from repeated episodes of pancreatic inflammation and associated fibrosis leading to the loss of functional exocrine and endocrine pancreatic function. The disease is manifested by abdominal pain, deterioration in quality of life, food maldigestion and malabsorption, diabetes, and an increased risk for pancreatic adenocarcinoma. This review summarizes the latest evidence on the diagnosis and management of chronic pancreatitis and its manifestations. In particular, this review discusses advances in understanding of the role of genetic disorders in the mechanisms of the disease and surgical options for patients refractory to medical therapy. Furthermore, clinical trials are under way to develop medical therapeutics.

Current and Future Therapeutic Approaches of Exocrine Pancreatic Insufficiency in Children with Cystic Fibrosis in the Era of Personalized Medicine

This review presents current updates of pancreatic enzyme replacement therapy in children with cystic fibrosis based on literature published in the last decade and some special considerations regarding pancreatic enzyme replacement therapy in the era of new therapies, such as cystic fibrosis transmembrane conductance regulator modulator therapies. Few articles evaluate the efficacy of pancreatic enzyme replacement therapy in the pediatric population, and most studies also included children and adults with cystic fibrosis. Approximately 85% of cystic fibrosis patients have exocrine pancreatic insufficiency and need pancreatic enzyme replacement therapy. Fecal elastase is the most commonly used diagnostic test for exocrine pancreatic insufficiency, although this value can fluctuate over time. While it is used as a diagnostic test, it cannot be used for monitoring the effectiveness of pancreatic enzyme replacement therapy and for adjusting doses. Pancreatic enzyme replacement therapy, the actual treatment for exocrine pancreatic insufficiency, is essential in children with cystic fibrosis to prevent malabsorption and malnutrition and needs to be urgently initiated. This therapy presents many considerations for physicians, patients, and their families, including types and timing of administration, dose monitoring, and therapy failures. Based on clinical trials, pancreatic enzyme replacement therapy is considered effective and well-tolerated in children with cystic fibrosis. An important key point in cystic fibrosis treatment is the recent hypothesis that cystic fibrosis transmembrane conductance regulator modulators could improve pancreatic function, further studies being essential. Pancreatic enzyme replacement therapy is addressed a complication of the disease (exocrine pancreatic insufficiency), while modulators target the defective cystic fibrosis transmembrane conductance regulator protein. Exocrine pancreatic insufficiency in cystic fibrosis remains an active area of research in this era of cystic fibrosis transmembrane conductance regulator modulator therapies. This new therapy could represent an example of personalized medicine in cystic fibrosis patients, with each class of modulators being addressed to patients with specific genetic mutations.

Prepuberal insulin secretory indices are long-term predictors of short adult stature in cystic fibrosis

Objective

Diabetes is a frequent comorbidity in cystic fibrosis (CF), related to multiple unfavorable outcomes. During the progression of β-cell dysfunction to diabetes, insulin deficiency could possibly reduce the anabolic support to grow even in the absence of significant glycemic derangements. To test this hypothesis, we evaluated whether prepuberal insulin secretory indices are independent predictors of adult height.

Design

Observational cohort study.

Research design and methods

A longitudinal analysis of 66 CF patients (33 females) from an ongoing cohort received at prepuberal age (median age of 12 years) modified 3-h oral glucose tolerance tests with 30-min insulin and C-peptide sampling, modeling of insulin secretory and sensitivity parameters, anthropometric evaluation. The latter was repeated when adults after a median follow-up of 9 years.

Results

In alternative models, we found a positive association with either basal insulin secretion (mean 0.22, 95% CI 0.01, 0.44 z-scores) or prepuberal β-cell glucose sensitivity (mean 0.23, 95% CI 0.00, 0.46 z-scores) and adult height, while total insulin secretion was negatively related to adult height (mean -0.36, 95% CI -0.57, -0.15 z-scores or mean -0.42, 95% CI -0.69, -0.16 z-scores, respectively). The high total insulin secretion of low adult height patients was mainly due to late (>60 min) secretion and was associated with a worse glucose response during OGTT.

Conclusions

Abnormal insulin secretion associated with high glucose response during OGTT predicts a decrease in adult height z-score. Our results suggest that insulin secretory defects in CF affect growth prior to the development of fasting hyperglycemia.

Assessment of Exocrine Function of Pancreas Following Pancreaticoduodenectomy

Pancreatic exocrine insufficiency (PEI) is a common long-term complication after pancreaticoduodenectomy (PD) and is observed in 23-80% of patients. As the postoperative mortality after PD has substantially decreased, it warrants more attention on the diagnosis and treatment of functional long-term consequences after PD. These include PEI and endocrine insufficiency that can result in significant nutritional impairment and often adversely impacts quality of life (QOL) of the patient. A PubMed search was performed for articles using key words "pancreatic exocrine insufficiency"; "pancreaticoduodenectomy"; "quality of life after pancreaticoduodenectomy"; "stool elastase"; "direct, indirect tests for pancreatic exocrine insufficiency"; "pancreatic enzyme replacement therapy." Relevant studies were shortlisted and analyzed. This review summarizes relevant studies addressing PEI following PD. We also discuss functional changes after PD, risk factors and predictive factors for postoperative PEI, clinical symptoms, direct and indirect tests for estimation of PEI, pancreatic enzyme replacement therapy (PERT), and QOL after pancreatic resection for malignancy. It was found that significant PEI occurs in most patients following PD. Fecal elastase 1 is an easy indirect test and should be performed routinely in both symptomatic and asymptomatic patients after PD. PERT should be considered in every patient after PD with the aim to improve the QOL and perhaps even their long time survival.

Diagnostic Performance of Measurement of Fecal Elastase-1 in Detection of Exocrine Pancreatic Insufficiency: Systematic Review and Meta-analysis

BACKGROUND & AIMS

Tests to quantify fecal levels of chymotrypsin like elastase family member 3 (CELA3 or elastase-1) in feces are widely used to identify patients with exocrine pancreatic insufficiency (EPI). However, the diagnostic accuracy of this test, an ELISA, is not clear. We performed a systematic review and meta-analysis to determine the accuracy of measurement of fecal elastase-1 in detection of EPI.

METHODS

We searched PubMed, Embase, and reference lists for articles through November 2016 describing studies that compared fecal level of elastase-1 with results from a reference standard, direct method (secretin stimulation test), or indirect method (measurement of fecal fat) for detection of EPI. Sensitivity and specificity values were pooled statistically using bivariate diagnostic meta-analysis.

RESULTS

We included total of 428 cases of EPI and 673 individuals without EPI (controls), from 14 studies, in the meta-analysis. The assay for elastase-1, compared to secretin stimulation test, identified patients with pancreatic insufficiency with a pooled sensitivity value of 0.77 (95% CI, 0.58-0.89) and specificity value of 0.88 (95% CI, 0.78-0.93). In an analysis of 345 cases of EPI and 312 controls, from 6 studies, the fecal elastase-1 assay identified patients with EPI with a pooled sensitivity value of 0.96 (95% CI, 0.79-0.99) and specificity value of 0.88 (95% CI, 0.59-0.97), compared to quantitative fecal fat estimation. In patients with low pre-test probability of EPI (5%), the fecal elastase-1 assay would have a false-negative rate of 1.1% and a false-positive rate of 11%, indicating a high yield in ruling out EPI but not in detection of EPI. In contrast, in patients with high pre-test probability of EPI (40%), approximately 10% of patients with EPI would be missed (false negatives).

CONCLUSIONS

In a systematic review and meta-analysis of studies that compared fecal level of elastase-1 for detection of EPI, we found that normal level of elastase-1 (above 200 mcg/g) can rule out EPI in patients with a low probability of this disorder (such as those with irritable bowel syndrome with diarrhea). However, in these patients, an abnormal level of elastase-1 (below 200 mcg/g) has a high false-positive rate.

Pancreatic exocrine insufficiency following acute pancreatitis: Systematic review and study level meta-analysis

OBJECTIVES

This study systematically explores the prevalence of pancreatic exocrine insufficiency (PEI) after acute pancreatitis in different subgroups of etiology (biliary/alcoholic/other), disease severity and follow-up time (<12, 12-36 and > 36 months after index admission).

METHODS

PubMed and EMBASE databases were searched, 32 studies were included in this study level meta-analysis.

RESULTS

In a total of 1495 patients with acute pancreatitis, tested at a mean of 36 months after index admission, the pooled prevalence of PEI was 27.1% (95%-confidence interval [CI]: 20.3%-35.1%). Patients from seven studies (n = 194) underwent direct tests with pooled prevalence of 41.7% [18.5%-69.2%]. Patients from 26 studies (n = 1305) underwent indirect tests with pooled prevalence of 24.4% [18.3%-31.8%]. In subgroup analyses on patients that underwent fecal elastase-1 tests, PEI occurred more often in alcoholic pancreatitis (22.7% [16.6%-30.1%]) than in biliary pancreatitis (10.2% [6.2%-16.4%]) or other etiology (13.4% [7.7%-22.4%]; P = 0.02). Pooled prevalence of PEI after mild and severe pancreatitis was 19.4% [8.6%-38.2%] and 33.4% [22.6%-46.3%] respectively in studies using fecal elaste-1 tests (P = 0.049). Similar results were seen in patients without (18.9% [9.3%-34.6%]) and with necrotizing pancreatitis (32.0% [18.2%-49.8%]; P = 0.053). Over time, the prevalence of PEI decreased in patients who underwent the fecal elastase-1 test and increased in patients who underwent the fecal fat analysis.

CONCLUSIONS

After acute pancreatitis, a quarter of all patients develop PEI during follow-up. Alcoholic etiology and severe and necrotizing pancreatitis are associated with higher risk of PEI. The prevalence of PEI may change as time of follow-up increases.

Exocrine Dysfunction Correlates with Endocrinal Impairment of Pancreas in Type 2 Diabetes Mellitus

BACKGROUND

Diabetes mellitus (DM) is a chronic abnormal metabolic condition, which manifests elevated blood sugar level over a prolonged period. The pancreatic endocrine system generally gets affected during diabetes, but often abnormal exocrine functions are also manifested due to its proximity to the endocrine system. Fecal elastase-1 (FE-1) is found to be an ideal biomarker to reflect the exocrine insufficiency of the pancreas.

AIM

The aim of this study was conducted to assess exocrine dysfunction of the pancreas in patients with type-2 DM (T2DM) by measuring FE levels and to associate the level of hyperglycemia with exocrine pancreatic dysfunction.

METHODOLOGY

A prospective, cross-sectional comparative study was conducted on both T2DM patients and healthy nondiabetic volunteers. FE-1 levels were measured using a commercial kit (Human Pancreatic Elastase ELISA BS 86-01 from Bioserv Diagnostics). Data analysis was performed based on the important statistical parameters such as mean, standard deviation, standard error, t-test-independent samples, and Chi-square test/cross tabulation using SPSS for Windows version 20.0.

RESULTS

Statistically nonsignificant (P = 0.5051) relationship between FE-1 deficiency and age was obtained, which implied age as a noncontributing factor toward exocrine pancreatic insufficiency among diabetic patients. Statistically significant correlation (P = 0.003) between glycated hemoglobin and FE-1 levels was also noted. The association between retinopathy (P = 0.001) and peripheral pulses (P = 0.001) with FE-1 levels were found to be statistically significant.

CONCLUSION

This study validates the benefit of FE-1 estimation, as a surrogate marker of exocrine pancreatic insufficiency, which remains unmanifest and subclinical.

Less common etiologies of exocrine pancreatic insufficiency

Exocrine pancreatic insufficiency (EPI), an important cause of maldigestion and malabsorption, results from primary pancreatic diseases or secondarily impaired exocrine pancreatic function. Besides cystic fibrosis and chronic pancreatitis, the most common etiologies of EPI, other causes of EPI include unresectable pancreatic cancer, metabolic diseases (diabetes); impaired hormonal stimulation of exocrine pancreatic secretion by cholecystokinin (CCK); celiac or inflammatory bowel disease (IBD) due to loss of intestinal brush border proteins; and gastrointestinal surgery (asynchrony between motor and secretory functions, impaired enteropancreatic feedback, and inadequate mixing of pancreatic secretions with food). This paper reviews such conditions that have less straightforward associations with EPI and examines the role of pancreatic enzyme replacement therapy (PERT). Relevant literature was identified by database searches. Most patients with inoperable pancreatic cancer develop EPI (66%-92%). EPI occurs in patients with type 1 (26%-57%) or type 2 diabetes (20%-36%) and is typically mild to moderate; by definition, all patients with type 3c (pancreatogenic) diabetes have EPI. EPI occurs in untreated celiac disease (4%-80%), but typically resolves on a gluten-free diet. EPI manifests in patients with IBD (14%-74%) and up to 100% of gastrointestinal surgery patients (47%-100%; dependent on surgical site). With the paucity of published studies on PERT use for these conditions, recommendations for or against PERT use remain ambiguous. The authors conclude that there is an urgent need to conduct robust clinical studies to understand the validity and nature of associations between EPI and medical conditions beyond those with proven mechanisms, and examine the potential role for PERT.

Chronic Pancreatitis: Current Status and Challenges for Prevention and Treatment

This paper reviews the current status of our understanding of the epidemiology, diagnosis, and management of the continuum of pancreatic diseases from acute and recurrent acute pancreatitis to chronic pancreatitis and the diseases that are often linked with pancreatitis including diabetes mellitus and pancreatic cancer. In addition to reviewing the current state of the field, we identify gaps in knowledge that are necessary to address to improve patient outcomes in these conditions.

Potential for Screening for Pancreatic Exocrine Insufficiency Using the Fecal Elastase-1 Test

The early diagnosis of pancreatic exocrine insufficiency (PEI) is hindered because many of the functional diagnostic techniques used are expensive and require specialized facilities, which prevent their widespread availability. We have reviewed current evidence in order to compare the utility of these functional diagnostic techniques with the fecal elastase-1 (FE-1) test in the following three scenarios: screening for PEI in patients presenting with symptoms suggestive of pancreatic disease, such as abdominal pain or diarrhea; determining the presence of PEI in patients with an established diagnosis of pancreatic disease, such as chronic pancreatitis or cystic fibrosis; determining exocrine status in disorders not commonly tested for PEI, but which have a known association with this disorder. Evidence suggests the FE-1 test is reliable for the evaluation of pancreatic function in many pancreatic and non-pancreatic disorders. It is non-invasive, is less time-consuming, and is unaffected by pancreatic enzyme replacement therapy. Although it cannot be considered the gold-standard method for the functional diagnosis of PEI, the advantages of the FE-1 test make it a very appropriate test for screening patients who may be at risk of this disorder.

Nutritional Status Improved in Cystic Fibrosis Patients with the G551D Mutation After Treatment with Ivacaftor

BACKGROUND

The cystic fibrosis (CF) transmembrane conductance regulator (CFTR) gating mutation G551D prevents sufficient ion transport due to reduced channel-open probability. Ivacaftor, an oral CFTR potentiator, increases the channel-open probability.

AIM

To further analyze improvements in weight and body mass index (BMI) in two studies of ivacaftor in patients aged ≥6 years with CF and the G551D mutation.

METHODS

Patients were randomized 1:1 to ivacaftor 150 mg or placebo every 12 h for 48 weeks. Primary end point (lung function) was reported previously. Other outcomes included weight and height measurements and CF Questionnaire-Revised (CFQ-R).

RESULTS

Studies included 213 patients (aged ≤ 20 years, n = 105; aged > 20 years, n = 108). In patients ≤20 years, adjusted mean change from baseline to week 48 in body weight was 4.9 versus 2.2 kg (ivacaftor vs. placebo, p = 0.0008). At week 48, change from baseline in mean weight-for-age z-score was 0.29 versus -0.06 (p < 0.0001); change in mean BMI-for-age z-score was 0.26 versus -0.13 (p < 0.0001). In patients >20 years, adjusted mean change from baseline to week 48 in body weight was 2.7 versus -0.2 kg (p = 0.0003). Mean BMI change at week 48 was 0.9 versus -0.1 kg/m(2) (p = 0.0003). There was no linear correlation evident between changes in body weight and improvements in lung function or sweat chloride. Significant CFQ-R improvements were seen in perception of eating, body image, and sense of ability to gain weight.

CONCLUSIONS

Nutritional status improved following treatment with ivacaftor for 48 weeks.

Diagnosis of Exocrine Pancreatic Insufficiency

OPINION STATEMENT

The accurate diagnosis of exocrine pancreatic insufficiency (EPI) helps identify those in need of pancreatic enzyme replacement therapy. Conversely, ruling out EPI identifies those in which additional evaluation should be pursued to explain their symptoms. There are many available tests that can be used to diagnose EPI; however, the tests must be tailored to each clinical scenario. Tests that are convenient but less accurate (e.g., fecal elastase-1, qualitative fecal fat determination) are best suited for patients with a high pretest probability of EPI. In contrast, tests that are highly accurate but more cumbersome (e.g., endoscopic pancreatic function testing, 72-h fecal fat collection) are favored in patients suspected to have mild EPI or an early stage of chronic pancreatitis. Additional research is needed to identify a more convenient means of accurately diagnosing at all stages of EPI.

Current options for the diagnosis of chronic pancreatitis

The diagnostic options for chronic pancreatitis have evolved over recent years. The previous gold standard references for structural imaging and exocrine pancreatic function testing have both been supplanted and redesigned. Endoscopic retrograde pancreatography has now been overtaken by endoscopic ultrasound and magnetic resonance cholangiopancreatography, whilst the old technique for Dreiling tube pancreatic function testing has now been replaced by the endoscopic pancreatic function test. New advances in endoscopic ultrasound elastography have also extended the options for evaluating pancreatic masses to differentiate mass-forming chronic pancreatitis from malignancy. Genetic contribution to chronic pancreatitis is also now more widely recognized than ever before.

Evolution of pancreatic function during the first year in infants with cystic fibrosis

OBJECTIVE

To describe pancreatic function during the first year of life in infants diagnosed with cystic fibrosis (CF) using serial fecal elastase measurements.

STUDY DESIGN

This was a longitudinal study of 82 infants diagnosed with CF through newborn screening. Monthly stool samples were sent to a central laboratory for fecal elastase measurements.

RESULTS

A total of 61 infants had an initial stool sample obtained at age <3.5 months and a final stool sample obtained at age >9 months. Twenty-six of 29 infants with a fecal elastase value <50 μg/g at study entry had a fecal elastase value <200 μg/g (the accepted cutoff value for pancreatic insufficiency) on all measurements during the year; all 29 had a value <200 μg/g at the end of the study. Of the 48 infants with initial fecal elastase value <200 μg/g, 13 had at least 1 fecal elastase value >200 μg/g but had a final stool fecal elastase value <200 μg/g; however, 4 infants with an initial fecal elastase value <200 μg/g ended the year with a value >200 μg/g. Eleven of 13 infants with an initial fecal elastase value of >200 μg/g still had a value >200 μg/g at the end of the first year.

CONCLUSION

Infants with CF exhibit variability in fecal elastase values during the first year. Infants with a fecal elastase level of 50-200 μg/g at diagnosis should be treated with pancreatic enzyme replacement therapy, but fecal elastase should be remeasured at age 1 year to ensure that those with a falsely low value do not continue to receive pancreatic enzyme replacement therapy unnecessarily. Those with a fecal elastase value >200 μg/g initially can become pancreatic insufficient with time.

Comparison of diagnostic methods for pancreatic insufficiency in infants with cystic fibrosis

OBJECTIVE

The objective of the present study is to compare daily weight gain and laboratory analysis (72-hour fecal fat and steatocrit) with fecal elastase-1 (EL-1) when diagnosing pancreatic insufficiency (PI) in infants with cystic fibrosis (CF).

METHODS

A total of 39 infants with CF, diagnosed consecutively by newborn screening at 2 referral centers, were included in the study. Daily weight gain and results of laboratory analysis of stool samples were compared using the κ coefficient and the receiver operator characteristic (ROC) curve.

RESULTS

Using the criterion of low daily weight gain, the frequency of PI was 92.3%; using the 72-hour fecal fat, steatocrit, and fecal EL-1 tests, the frequency was 42.3%, 86.2%, and 84.6%, respectively. EL-1 was used as the reference test. It was observed that the criteria of low daily weight gain (<50th percentile) and abnormal steatocrit, used together, showed the highest sensitivity (91.3%) and specificity (83.3%) for the diagnosis of PI.

CONCLUSIONS

When fecal EL-1 analysis is not immediately available, low daily weight gain associated with abnormal steatocrit can be adopted as a criterion for initiating pancreatic enzyme replacement therapy in infants with CF; however, EL-1 testing should be performed later for confirmation of PI.

Ontogeny of oral drug absorption processes in children

INTRODUCTION

A large proportion of prescribed drugs to children are administered orally. Age-related change in factors affecting oral absorption can have consequences for drug dosing.

AREAS COVERED

For each process affecting oral drug absorption, a systematic search has been performed using Medline to identify relevant articles (from inception till February 2012) in humans. This review presents the findings on age-related changes of the following processes affecting oral drug absorption: gastric pH, gastrointestinal motility, bile salts, pancreatic function, intestinal pH, intestinal drug-metabolizing enzymes and transporter proteins.

EXPERT OPINION

Clinicians should bear in mind the ontogeny of oral drug absorption processes when prescribing oral drugs to children. The authors' review shows large information gaps on almost all drug absorption processes. It is important that more knowledge is acquired on intestinal transit time, intestinal pH and the ontogeny of intestinal drug-metabolizing enzymes and drug transporter proteins. Furthermore, the ultimate goal in this field should be to predict more precisely the oral disposition of drugs in children across the entire pediatric age range.

Chronic pancreatitis and exocrine insufficiency

The evaluation, management, and follow-up of patients with chronic pancreatitis (CP) can be simple, but it can also be complex, so having a good referral network of subspecialists experienced in this field is essential. Identifying the cause of CP requires a systematic review of the many potential causes when the cause is not obvious. The identification of patients with autoimmune CP is particularly important because treatment with steroids may be effective. Alterations in pain or other symptoms in patients with CP should not be attributed to worsening disease before evaluations for complications including malignancy are done.

Adaptive changes of pancreatic protease secretion to a short-term vegan diet: influence of reduced intake and modification of protein

In our previous study, we demonstrated that abstaining from meat, for 1 month, by healthy omnivores (lacto-ovovegetarian model) resulted in a statistical decrease in pancreatic secretion as measured by faecal elastase-1 output. However, no correlation between relative and non-relative changes of energy and nutrient consumption and pancreatic secretion was documented. Therefore, in the present study, we aimed to assess the changes of exocrine pancreatic secretion with a more restrictive dietetic modification, by applying a vegan diet. A total of twenty-one healthy omnivores (sixteen females and five males) participated in the prospective study lasting for 6 weeks. The nutrient intake and faecal output of pancreatic enzymes (elastase-1, chymotrypsin and lipase) were assessed twice during the study. Each assessment period lasted for 7 d: the first before the transition to the vegan diet (omnivore diet) and the second during the last week of the study (vegan diet). The dietary modification resulted in a significant decrease in faecal elastase-1 (P < 0·05) and chymotrypsin output (P < 0·04). The lipase excretion remained unchanged. The decrease in proteolytic enzymes was documented to be positively correlated with a decreased protein intake (P < 0·05). In addition, elastase-1 and chymotrypsin outputs were also related to the changes of protein type, plantv.animal (P < 0·04 andP < 0·03, respectively). It was concluded that significant reduction and modification of protein intake due to a short-term vegan diet resulted in an adaptation of pancreatic protease secretion in healthy volunteers.

The role of fecal elastase-1 in detecting exocrine pancreatic disease

Exocrine pancreatic disease is thought to be uncommon in clinical practice and usually secondary to excess alcohol intake. Although excess alcohol intake does account for many cases of exocrine pancreatic disease, other conditions are associated with exocrine pancreatic insufficiency and such dysfunction perhaps occurs more frequently than conventionally expected. A reliable, patient-friendly, cheap and easy to use test for exocrine pancreatic disease is yet to be established; however, in many countries the main (and often only available) method of assessment of exocrine pancreatic function is the fecal-elastase-1 test. This Review examines the role of fecal-elastase-1 testing in detecting exocrine pancreatic insufficiency in a number of gastrointestinal and nongastrointestinal conditions and determines the value of pancreatic enzyme supplementation in these settings.

Occlusal asymmetries in children with congenital hip dislocation

Developmental dysplasia of the hip (DDH) has been associated with other congenital postural deformities and associated with asymmetric features in the body. The aim of this study was to examine the associations between developmental DDH and malocclusions in preschool and school children. The subjects were 60 children (40 girls and 20 boys) born during 1997-2001 in Northern Ostrobothnia Hospital District and having developmental DDH and treated by Von Rosen method. The control group consisted of 71 Finnish children (46 girls and 25 boys) matched by age and gender. Children participated the cross-sectional study at the age of 5-10 years; the mean age of the DDH children was 8.0 (SD 1.4) and controls 7.9 (SD 1.4) years. Dental examinations, intra-oral photographs, and clinical examination including growth measurements were carried out. The DDH children had significantly more lateral crossbites than controls (30/9.9 per cent; P < 0.003). Overall, 77.8 per cent of cases were unilateral crossbites and found more on the right side (50 per cent) compared to the left side (22.2 per cent). Girls had more crossbite compared to boys (77.8/22.2 per cent; odds ratio 2.53). Children with congenital hip dislocation are more predisposed to the asymmetric growth of occlusion and the development of crossbite. The genetic and environmental factors including intrauterine conditions in addition to the splint therapy may be possible influencing factors. This study will give additional information of the development of occlusal asymmetries and the multifactorial nature of the aetiology of lateral malocclusions.

Pancreatic insufficiency in adult celiac disease: do patients require long-term enzyme supplementation?

BACKGROUND

Celiac disease is associated with exocrine pancreatic insufficiency. We previously reported that in 30% (20/66) of adult celiac patients with current or persistent diarrhea the underlying cause was exocrine pancreatic insufficiency. Of these 20 patients, 19 initially improved on pancreatic supplementation. To date, there are no published longitudinal studies.

METHODS

The 20 patients who had initially received therapy for exocrine pancreatic insufficiency were prospectively followed-up for 4 years. Gastrointestinal symptoms, dietary adherence, celiac antibody status, and dose of enzyme supplementation were recorded. Fecal elastase-1 (Fel-1) was repeated to reassess exocrine pancreatic function.

RESULTS

In the study, 19/20 patients were reviewed, as one had died (mean age 59.7 years, 7 males). The mean duration of celiac disease was 13.2 years. Eleven out of nineteen were still taking enzyme supplementation at a mean dose of 45,000 units of lipase per day. Only 1/11 reported no symptomatic benefit and 8/19 patients had discontinued supplementation because their diarrhea had improved. In the whole group there was a significant increase in Fel-1 levels over time, with median values of 90 μg/g at 0 months, 212 μg/g at 6 months, and 365 μg/g at follow-up (45-66 months)(p < 0.0001).

CONCLUSIONS

Fecal elastase-1 is useful in identifying exocrine pancreatic insufficiency in adult celiac patients with diarrhea. Our longitudinal data suggests that pancreatic enzyme supplementation could be discontinued in a substantial proportion of patients as symptoms improve.

Acid steatocrit determination is not helpful in cystic fibrosis patients without or with mild steatorrhea

BACKGROUND

Most methods used for the assessment of severe steatorrhea in cystic fibrosis (CF) are sensitive. In fact, the tests show their usefulness in a borderline zone of the results. Yet, the existing data related to acid steatocrit (AS) are still contradictory. Therefore, in the present study we have aimed to assess CF patients without or with mild steatorhea (<10 g/day) and evaluate the applicability of AS in such a subset of patients.

PATIENTS AND METHODS

In fifty-five CF patients, AS, fecal fat concentration (FFC) and fecal fat excretion (FFE) in 1-day stool collection were assessed from one to three times (149 samples). In 50 subjects, FFC, FFE, and AS were available for 3 subsequent days. It allowed for the calculations based upon 3-day fecal fat balance study.

RESULTS

The correlations between FFE/FFC and AS based upon 1-day stool collection, although statistically significant, were rather weak (r = 0.208, P < 0.011; r = 0.362, P < 0.000006, respectively). The correlations between FFE/FFC and AS based upon the 3-day stool collection, although stronger, did not show values a linear relationship (r = 0.394, P < 0.005; r = 0.454, P < 0.001, respectively). With no regard to the cut-off level for AS (10% and 20%), sensitivity, specificity, negative, and positive predictive values in the determination of abnormal FFC and FFE were not satisfactory. The flow charts describing the accuracy of AS to determine FFE and FC revealed a high level of uncertainty.

CONCLUSIONS

AS does not reflect in a reliable way FFE in CF patients without or mild steatorrhea. Its applicability in the assessment of FFC in such patients has therefore limited practical value.

Efficacy and tolerability of Creon for Children in infants and toddlers with pancreatic exocrine insufficiency caused by cystic fibrosis: an open-label, single-arm, multicenter study

OBJECTIVES

To evaluate the efficacy and safety of a pancreatic enzyme preparation specifically developed for infants and small children with cystic fibrosis (CF).

METHODS

Twelve patients with CF younger than 24 months with pancreatic exocrine insufficiency and a coefficient of fat absorption (CFA) less than 70% were treated with Creon for Children (Solvay Pharmaceuticals GmbH, Hannover, Germany) minimicrospheres for 8 weeks. The primary end point was the mean change from baseline in the CFA after 2 weeks of treatment, based on 72-hour fat balance assessments.

RESULTS

Two weeks' treatment with Creon for Children resulted in a significant increase in the mean CFA from 58.0% at baseline to 84.7% (P=0.0013) in the full analysis sample. There was a significant reduction of mean stool fat (from 13.3 to 5.3 g/d; P=0.001) and mean fecal energy loss (from 238.5 to 137.9 kJ/d; P=0.018) at 2 weeks. Dietary fat intake did not change, whereas an improvement was observed in stool frequency and characteristics. Patient weight and height increased over 8 weeks of treatment. No serious adverse event was reported.

CONCLUSIONS

Creon for Children was well tolerated and significantly decreased fat malabsorption in infants with pancreatic exocrine insufficiency due to CF.

Tests of pancreatic exocrine function - clinical significance in pancreatic and non-pancreatic disorders

The pancreas functions as the main factory for digestive enzymes and therefore enables food utilisation. Pancreatic exocrine insufficiency, partial or complete loss of digestive enzyme synthesis, occurs primarily in disorders directly affecting pancreatic tissue integrity. However, other disorders of the gastrointestinal tract, such as coeliac disease, inflammatory bowel disease, Zollinger-Ellison syndrome or gastric resection can either mimic or cause pancreatic exocrine insufficiency. The overt clinical symptoms of pancreatic exocrine insufficiency are steatorrhoea and maldigestion, which frequently become apparent in advanced stages. Several direct and indirect function tests are available for assessment of pancreatic function but until today diagnosis of excretory insufficiency is difficult as in mild impairment clinically available function tests show limitations of diagnostic accuracy. This review focuses on diagnosis of pancreatic exocrine insufficiency in pancreatic and non-pancreatic disorders.

Exocrine pancreatic function testing in patients with cystic fibrosis and pancreatic sufficiency: a correlation study

OBJECTIVES

Most patients with cystic fibrosis (CF) have pancreatic insufficiency; however, 15% of the patients are pancreatic sufficient (PS). Several laboratory tests have been developed to distinguish between pancreatic insufficiency and PS. The gold standard to determine pancreatic function apart from direct pancreatic stimulation test is the 72-hour fecal fat excretion, expressed as coefficient of fat absorption (CFA). The aim was to test the correlation between 2 other tests, fecal elastase-1 and serum immunoreactive trypsinogen (IRT), as compared with fecal fat excretion.

PATIENTS AND METHODS

21 patients with CF-PS performed the 3 tests of fecal fat excretion, fecal elastase-1, and IRT. Correlation between the tests was evaluated by the kappa statistics test, sensitivity and specificity, and positive and negative predictive values.

RESULTS

CFA was abnormal in 5 patients, elastase was <200microg/g in 4 patients, and IRT was <20 ng/mL in 2 patients. The correlation between CFA and IRT was negative(kappa=-0.154), and between CFA and fecal elastase-1 was poor (kappa=0.213). The sensitivity, specificity, and positive and negative predictive values of IRT versus CFA were 0%, 88%, 0%, and 78%, and for fecal elastase-1 were 40%, 81%, 40%, and 81%, respectively.

CONCLUSIONS

In CF-PS, poor correlation was found between IRT, fecal elastase-1, and CFA, therefore neither fecal elastase-1 in the stool nor IRT in the serum reaches the sensitivity or the specificity of the fecal fat excretion. Thus, fecal fat excretion is required in patients with CF for evaluation of pancreatic function.

Development and validation of an improved test for the measurement of human faecal elastase-1

BACKGROUND

Human faecal elastase-1 (FE-1) is an established biochemical test for the investigation of pancreatic exocrine insufficiency. Conventional extraction methods for FE-1 analysis can give false-positive results with watery stools. This is a major limitation as patients investigated for pancreatic disease commonly produce such stools. We have developed an improved FE-1 test that overcomes water interference by measuring the enzyme in dried faeces.

METHODS

A novel collection device for FE-1 analysis that involves drying and weighing the stool sample was developed in our laboratory and compared with a conventional wet method, E1 Quick-Prep (Schebo, Biotech AG, Germany). The concentration of faecal FE-1 was determined using a commercially available enzyme-linked immunosorbent assay method (Schebo).

RESULTS

FE-1 values obtained using the new dry extraction procedure (mean 1777 microg/g dry stool) were higher when compared with the conventional wet analysis (mean 402 microg/g stool). A 1:2 dilution in water, mimicking a loose stool, was found to affect FE-1 results obtained using the conventional wet extraction procedure. The new dry extraction method gave consistent results when water content was varied in the original stool sample.

CONCLUSION

We have demonstrated that our new device overcomes water interference, allowing results to be obtained from stool samples that would otherwise be unsuitable for FE-1 analysis.

Usefulness of a 13C-labeled mixed triglyceride breath test for assessing pancreatic exocrine function after pancreatic surgery

BACKGROUND

Although the fecal elastase-1 test is a satisfactory pancreatic exocrine function test, breath tests that use stable isotopes have been developed recently as alternatives. We evaluated the usefulness of a (13)C-labeled mixed triglyceride breath test for assessing pancreatic exocrine function after pancreatic surgery.

METHODS

The breath test and the fecal elastase-1 test were performed on 7 healthy volunteers, 10 patients with chronic pancreatitis, and 95 patients after pancreatic surgery. The breath test was analyzed with isotope ratio mass spectrometry and the cumulative recovery of (13)CO(2) at 7 hours (% dose (13)C cum 7h) was calculated. The fecal elastase-1 concentration was determined immunoenzymatically.

RESULTS

Both the fecal elastase-1 concentration and the % dose (13)C cum 7h of chronic pancreatitis patients and pancreatic resection patients were less than those of healthy volunteers. In all subjects, % dose (13)C cum 7h correlated with the fecal elastase-1 concentration (n = 112, R(2) = 0.14, P < .01). Accuracy rates for clinical symptoms, including clinical steatorrhea, for the fecal test and the breath test were 62 and 88%, respectively.

CONCLUSION

The (13)C-labeled mixed triglyceride breath test might be more useful than the fecal elastase-1 test for evaluating pancreatic exocrine function after pancreatic resection.

Evaluation of a fecal pancreatic elastase-1 enzyme-linked immunosorbent assay: Assessment versus an established assay and implication in classifying pancreatic function

BACKGROUND

Disagreement continues regarding 2 fecal pancreatic elastase-1 (PE-1) ELISAs and their respective capabilities to assess pancreatic function.

METHODS

The BioServ Diagnostics polyclonal PE-1 ELISA was validated and its performance characteristics compared to the previously validated ScheBo Biotech monoclonal PE-1 ELISA. Split sample study results were analyzed by Deming regression and Bland-Altman plot analysis. Data mining was utilized to explore PE-1 distribution and evaluate PE-1 and fecal fat correlation.

RESULTS

Analysis demonstrates limited quantitative agreement; slope=0.9640, intercept=10.787, R(2)=0.633. Means were 228.8 and 226.2 microg PE-1/g stool for the polyclonal and monoclonal assays respectively. Bland-Altman analysis showed 91% of paired values within 2 SD of their means. There was good qualitative agreement when interpreted against established intervals with 91% of results equivalent in pancreatic function classification. The remaining 9% varied by one classification level with no bias evident. The distribution of PE-1 concentrations (n=400, 0-25 years) classified 78% of subjects with normal pancreatic function, 7% with moderate pancreatic insufficiency and 15% with severe insufficiency. There was little agreement between PE-1 and fecal fat results.

CONCLUSIONS

The polyclonal PE-1 ELISA is an acceptable alternative to the monoclonal PE-1 ELISA. PE-1 is a potential substitute for fecal fat for evaluating pancreatic function.

The changing face of the exocrine pancreas in cystic fibrosis: pancreatic sufficiency, pancreatitis and genotype

(Table is included in full-text article.)Cystic fibrosis (CF) is the most frequent cause of exocrine pancreatic insufficiency in childhood. The cystic fibrosis transmembrane conductance regulator (CFTR) gene encodes CFTR protein that functions as cyclic AMP-dependent chloride channel allowing the passage of anions and secondarily water into the lumen of pancreatic ducts. Luminal chlorides are exchanged for bicarbonates. The lack of CFTR channel or its disrupted function (being the consequence of CFTR gene mutations) results in reduced volume of more acidic secretion. It has been suggested that such a situation leads to the precipitation of highly concentrated protein-containing secretion with obstruction and organ damage. The intensity of this process determines the progression of the disease. Steatorrhea is the significant symptom of classical form of CF. Residual pancreatic secretion in a subset of patients, however, allows for normal lipid digestion and absorption. Previous cross-sectional clinical studies estimated that about 85-90% of CF patients in preschool, school and older age are pancreatic insufficient. More frequent detection of mild and nonclassic forms of CF leads to higher frequency of pancreatic sufficiency (PS). The potential decline of exocrine pancreatic function, however, should be always considered. All PS patients with at least one severe or unknown CFTR mutation should be longitudinally assessed for the progression of pancreatic dysfunction. Recurrent acute and chronic pancreatitis is not a rare clinical condition in PS patients with PS: it might be the presenting symptom, even preceding CF diagnosis by several years. Potential appearance of this complication in individuals with pancreatic insufficiency demands elucidation.

What and when to collect from infants with cystic fibrosis

Perspective on the papers by Cipolli et al and Hilliard et al (see pages 842 and 898)

Benefits of breastfeeding in cystic fibrosis: a single-centre follow-up survey

AIM

To study the effect of breastfeeding (BF) on growth, lung function and number of infections during the first 3 years of life in children with cystic fibrosis (CF).

MATERIAL AND METHODS

One hundred forty-six CF patients, 5-18 years old, were recruited at their annual care visit. Information about infant feeding, psychosocial and socioeconomic conditions and smoking exposure was obtained by interviews. Anthropometric parameters at 1 year of age and the number of infections and hospitalisations during the first 3 years of life were obtained from clinical charts. Anthropometrics and pulmonary function parameters were obtained at enrollment.

RESULTS

In CF patients, particularly those with pancreatic insufficiency, the prevalence of BF was lower than the general Italian population. After multivariate analysis patients with prolonged BF showed higher values of CED expiratory volume in 1 sec (FEV-1) (p = 0.001) and a lower number of infections during the first 3 years of life (p = 0.098).

CONCLUSION

Prolonged BF is beneficial in children with CF and may protect them against decline of pulmonary function. Particular attention should be paid to promote BF in infants with CF.

Is exocrine pancreatic insufficiency in adult coeliac disease a cause of persisting symptoms?

BACKGROUND

Patients with coeliac disease may have diarrhoea despite being on a gluten-free diet.

AIM

To assess whether exocrine pancreatic insufficiency causes persisting symptoms compared with controls, we determined whether pancreatic enzyme supplementation provided symptomatic benefit in coeliac patients with chronic diarrhoea.

METHODS

Patients (n = 259) were subdivided into four groups: (a) new coeliac disease (n = 57), (b) coeliac disease patients on a gluten-free diet without gastrointestinal symptoms (n = 86), (c) coeliac disease patients on a gluten-free diet with chronic diarrhoea (n = 66) and (d) patients with chronic diarrhoea without coeliac disease (n = 50). Stool frequency and weight, before and after treatment with pancreatic enzyme supplementation were recorded.

RESULTS

The prevalence of a low faecal elastase-1 within the groups was: group (A) six of 57 (11%), group (B) five of 86 (6%), group (C) 20 of 66 (30%) and group (D) two of 50 (4%). Low faecal elastase-1 was more frequent in coeliac disease patients with chronic diarrhoea vs. other subgroups of coeliac disease (P < or = 0.0001) and controls (P < or = 0.0003). In 18 of 20 stool frequency reduced following pancreatic enzyme supplementation from four per day to one (P < or = 0.001). No weight increase (P = 0.3) was observed.

CONCLUSIONS

Low faecal elastase is common in patients with coeliac disease and chronic diarrhoea, suggesting exocrine pancreatic insufficiency. In this group of patients, pancreatic enzyme supplementation may provide symptomatic benefit.

Human pancreatic digestive enzymes

A primary function of the pancreas is to produce digestive enzymes that are delivered to the small intestine for the hydrolysis of complex nutrients. Much of our understanding of digestive enzymes comes from studies in animals. New technologies and the availability of the sequence of the human genome allow for a critical review of older reports and assumptions based on animal studies. This report updates our understanding of human pancreatic digestive enzymes with a focus on new insights into the biology of human proteases, lipases and amylases.

Normal pancreatic secretion in children with progressive familial intrahepatic cholestasis type 1

OBJECTIVE

Progressive familial intrahepatic cholestasis type 1 (PFIC1) is a rare, autosomal, recessive, inherited disease resulting from mutations in the ATP8B1 gene which is expressed at high levels in the small intestine and pancreas and at lower levels in the liver. Given this expression pattern, patients might be expected to have a pancreatic phenotype. Although pancreatitis and steatorrhea have been reported in patients with PFIC1, the available data on pancreatic function are not fully convincing. Therefore, the objective of this study was to assess exocrine pancreatic function in patients with PFIC1.

MATERIAL AND METHODS

Three subjects with a diagnosis of PFIC1 were included in the study. The diagnosis was confirmed by molecular analysis of ATP8B1. Prior to surgical treatment (biliary diversion), two patients had steatorrhea and in the third patient, a borderline value for fecal fat excretion was documented. In one patient, liver transplantation also was subsequently performed. Exocrine pancreatic secretion was assessed by the use of fecal elastase-1 and chymotrypsin tests. Fecal lipase concentrations were determined in order to exclude isolated lipase deficiency. Other typical diagnostic procedures were performed annually.

RESULTS

The results of the fecal tests were within the normal range. None of the three patients experienced any episodes that could be related to acute or chronic pancreatitis. Laboratory tests including serum amylase and lipase tests were always normal. Abdominal ultrasonography findings did not show any pancreatic pathology.

CONCLUSIONS

Pancreatic secretion in the study patients with progressive familial intrahepatic cholestasis type 1 was normal. The observed steatorrhea was not related to pancreatic insufficiency.

Unresponsive or non-compliant steatorrhea in cystic fibrosis?

In 105 pancreatic insufficient CF patients (steatorrhea and low fecal elastase-1 concentrations), the effectiveness of pancreatic enzyme therapy (PET) has been assessed (fecal fat losses and coefficient of fat reabsorption). Eight unresponsive subjects were checked for PET compliance with fecal chymotrypsin assay. Three patients were documented to be non-compliant. Unresponsive patients should undergo evaluation for PET compliance.

Dietary and circulating polyunsaturated fatty acids in cystic fibrosis: are they related to clinical outcomes?

OBJECTIVE

To assess the relationship between dietary intakes, plasma phospholipid (PL) fatty acid profile and clinical parameters in children with cystic fibrosis (CF) in comparison to healthy controls.

PATIENTS AND METHODS

A cross-sectional survey including 37 patients with CF (ages 8.0 +/- 2.9 yrs) and a reference group of 68 healthy children (ages 8.0 +/- 0.7 yrs) was carried out by means of a food-frequency questionnaire. At enrollment, all subjects underwent blood sampling for plasma PL fatty acids (FA). In CF patients, pulmonary function tests (forced expiratory volume in 1 second and forced vital capacity), anthropometric measurements and the Shwachman score were also determined.

RESULTS

In CF patients, mean z score for weight and height (-0.35 +/- 1.16 and -0.28 +/- 0.99) were lower than controls (0.83 +/- 1.73 and 0.55 +/- 1.11, respectively). Patients with CF showed higher energy intakes (110 +/- 43 kcal/d) compared with controls (75 +/- 22 kcal/d; P < 0.0001), with higher intake of total (saturated and monounsaturated) fats and lower intake of polyunsaturated FA (3.9 +/- 1.0% of total macronutrient intake vs 4.3 +/- 1.2%, P = 0.05). In CF patients, plasma and PL levels of linoleic and docosahexaenoic acids were lower, whereas those of arachidonic acid were similar compared with controls. The Shwachman score showed significant positive associations with plasma PL levels of arachidonic acid and total n-6 long-chain FA (r = 0.32, P = 0.05, and r = 0.35, P = 0.03, respectively).

CONCLUSIONS

The data give suggestions that fat intake and CF-associated biomechanisms are bound in a vicious circle, concurring to create the clinical and biochemical picture of CF. The quantity and quality of fat supplementation in CF need careful attention to balance the fat supply with polyunsaturated FA.

Fecal elastase-1: utility in pancreatic function in cystic fibrosis

Early detection and management of pancreatic insufficiency is essential to optimize health and outcomes in cystic fibrosis patients. The gold standard measures for assessment of pancreatic function are direct pancreatic stimulation tests, which have numerous limitations. Estimation of fecal elastase-1 level to determine pancreatic function is an attractive alternative as the test is simple, rapid, cost-effective and easy to perform even in children. This review summarizes the data from studies reflecting the validity, limitation and advantages of fecal elastase-1 in assessing pancreatic function in cystic fibrosis patients.

Exocrine pancreatic function in children with progressive familial intrahepatic cholestasis type 2

In progressive familial intrahepatic cholestasis type 2 (PFIC-2), severe steatorrhea is often documented. However, pancreatic exocrine secretion has not yet been studied. In 14 children with PFIC-2, pancreatic function was assessed using standard fecal tests. Normal fecal lipase concentrations excluded isolated lipase deficiency. No differences in fecal elastase-1 concentrations and chymotrypsin activities were detected between PFIC-2 patients with or without steatorrhea, nor between these patients and healthy subjects. In conclusion, pancreatic exocrine function in patients with PFIC-2 is normal. Steatorrhea observed in those patients is not related to pancreatic insufficiency.

[Fecal elastase-1: a useful test in pediatric practice]

AIM

To study fecal elastase-1 (E1F) and chymotrypsin (ChT) in stools for the diagnosis of pancreatic insufficiency in pediatric practice.

MATERIALS AND METHODS

E1F and ChT were measured in stools of 198 children divided in 3 groups: 49 children without any digestive disease (group A), 71 children with pancreatic diseases (group B), and 78 children with non-pancreatic digestive diseases (group C).

RESULTS

In group B, E1F values were very low in 64 children and normal in 7 children without pancreatic insufficiency (6 children with cystic fibrosis and 1 with chronic pancreatitis). ChT values were normal in children without pancreatic insufficiency but also in half of children treated with pancreatic enzymes. Decreased E1F values were seen in 2 children (4%) in the group A and 22 children (28%) in the group C, especially those with acute gastroenteritis or celiac disease.

CONCLUSION

E1F is a simple, non-invasive, useful tool for the diagnosis of pancreatic insufficiency in children with growth failure or chronic diarrhea, and those with cystic fibrosis. Nevertheless, low values may be found in diseases with villous atrophy or very liquid stools.

Pancreatitis among patients with cystic fibrosis: correlation with pancreatic status and genotype

OBJECTIVE

Pancreatitis is an infrequent complication among patients with cystic fibrosis (CF). It has mainly been reported for patients with pancreatic sufficiency (PS). Previous studies involved only a small number of patients because they contained data from single centers. The aim of this study was to evaluate the incidence of pancreatitis in a large heterogeneous CF population, to determine the relationship with pancreatic function, and to assess whether pancreatitis is associated with specific CFTR mutations.

METHODS

Physicians caring for patients with CF were approached through the CF Thematic Network or through the European Cystic Fibrosis Foundation newsletter. They were asked to provide data on their current patient cohort through a standardized questionnaire and to report how many patients they had ever diagnosed as having pancreatitis. A detailed questionnaire was then sent, to be filled out for all of their patients for whom pancreatitis had ever occurred. We defined pancreatitis as an episode of acute abdominal pain associated with serum amylase levels elevated above the ranges established by each participating center's laboratory. General clinical data included age, genotype, age at diagnosis of CF, sweat chloride concentrations, pancreatic status, biometric findings, and respiratory status. CFTR mutations were also reported according to the functional classification of classes I to V. Patients were categorized as having PS, pancreatic insufficiency (PI), or PI after an initial period of PS. PI was defined as a 72-hour stool fat loss of >7 g/day, fat absorption of <93%, or fecal elastase levels of <200 microg/g feces. Clinical data on pancreatitis included age at the first episode, amylase and lipase levels, possible triggers, and occurrence of relapses or complications.

RESULTS

A total of 10071 patients with CF, from 29 different countries, who were undergoing follow-up monitoring in 2002 were surveyed. Among this group, pancreatitis had ever been diagnosed for 125 patients (1.24%; 95% confidence interval [CI]: 1.02-1.46%). There was variability in the reported rates of pancreatitis for different countries. Twenty-six centers in 15 different countries sent detailed clinical data on their patients with pancreatitis and on their whole CF clinic. This involved 3306 patients with CF and 61 cases of pancreatitis, leading to a prevalence of 1.84% (95% CI: 1.39-2.30%). The mean age of the patients with pancreatitis ever was 24.4 years (SD: 10.8 years). The first episode of pancreatitis occurred at a mean age of 19.9 years (SD: 9.6 years). The median serum amylase level at the time of pancreatitis was 746 IU/L (interquartile range: 319-1630 IU/L), and the median lipase level was 577 IU/L (interquartile range: 229-1650 IU/L). The majority of patients had PS (34 of 61 patients, 56%; 95% CI: 43-68%). Pancreatitis occurred for 15 patients with PI (25%; 95% CI: 14-35%). Eight patients developed PI after initial PS. The occurrence of pancreatitis among patients with PS was 34 cases per 331 patients, ie, 10.27% (95% CI: 7.00-13.55%); the occurrence of pancreatitis among patients with PI was 15 cases per 2971 patients, ie, 0.5% (95% CI: 0.25-0.76%). The mean age (in 2002) of the CF cohort with pancreatitis did not differ between the PS and PI subgroups. The forced expiratory volume in 1 second was significantly lower among the patients with PI than among the patients with PS, ie, 65% (SEM: 7%) vs 79% (SEM: 4%). The mean age at the occurrence of pancreatitis and the amylase and lipase levels during pancreatitis were not different for patients with pancreatitis and PI versus PS. In the group with PS, 31 of 34 patients carried at least 1 class IV or V CFTR mutation. In the groups with PI and PI after PS, 5 of 15 patients and 3 of 8 patients, respectively, carried 2 class I, II, or III CFTR mutations. Relapses and/or evolution to chronic pancreatitis occurred for 42 patients. Pancreatitis preceded the diagnosis of CF in 18 of 61 cases. These patients were significantly older than the rest of the cohort, ie, age of 28.4 years (SEM: 3.4 years) vs 22.7 years (SEM: 1.3 years). Their median age at the diagnosis of CF was also significantly greater, ie, 21.5 years (interquartile range: 11.9-31 years) vs 7.6 years (interquartile range: 0.4-17.0 years). However, the ages at the occurrence of pancreatitis were similar, ie, 21.0 years (SEM: 3.0 years) vs 19.5 years (SEM: 1.2 years).

CONCLUSIONS

This study of 10071 patients with CF from 29 different countries revealed an estimated overall occurrence of pancreatitis among patients with CF of 1.24% (95% CI: 1.02-1.46%). The incidence of pancreatitis was much higher among patients with PS. However, pancreatitis was also reported for 15 patients with PI from 11 centers in 9 different countries. A correct diagnosis of pancreatitis for the reported patients with PI was supported by amylase and lipase levels increased above 500 IU/L, similar to those for patients with PS and pancreatitis. A correct diagnosis of PI for these patients with pancreatitis was supported by the adequacy of the methods used. We chose the cutoff values used to distinguish between patients with PI and control subjects without gastrointestinal disease. For one half of the patients, the diagnosis of PI was established on the basis of low levels of stool elastase (mean: 97 mug/g stool). With a cutoff value of 200 microg/g stool, this noninvasive test has high sensitivity (>95%) and high specificity (>90%) to differentiate patients with PI from control subjects with normal pancreatic function. For the other one half of the patients with PI in the cohort, the pancreatic status was determined on the basis of the 3-day fecal fat balance, with the widely used cutoff value of >7 g of fat loss per day. The most likely reason for pancreatitis occurring among patients with PI is that some residual pancreatic tissue is present among these patients. Pancreatitis is a rare complication among patients with CF. It occurred for 1.24% (95% CI: 1.02-1.46%) of a large CF cohort. Pancreatitis occurs mainly during adolescence and young adulthood. It is much more common among patients with CF and PS (10.3%), but it can occur among patients with PI (0.5%). Pancreatitis can be the first manifestation of CF. Pancreatitis was reported for patients carrying a wide range of mutations.

Fecal elastase: pancreatic status verification and influence on nutritional status in children with cystic fibrosis

OBJECTIVES

To evaluate fecal elastase 1 (FE) levels in young children with cystic fibrosis and pancreatic insufficiency and to explore the relationship between FE and growth, nutrition, pulmonary status and fat absorption over a 24-month period.

METHODS

FE, indicating pancreatic lipase activity, was assessed in children (6.0 to 8.9 years of age) with cystic fibrosis and pancreatic insufficiency. FE >15 microg/g stool was defined as residual pancreatic activity, suggesting some pancreatic function, and FE </=15 microg/g stool was defined as no pancreatic activity, suggesting pancreatic insufficiency. Seven-day weighed food records were collected and coefficient of fat absorption was calculated using dietary records and 72-hour stool collection. Height adjusted for mid-parental height, weight, body mass index, upper arm muscle area and upper arm fat area were measured and Z scores were calculated. Forced expiratory volume in 1 second was the measure of pulmonary function.

RESULTS

Ten children (12%) had residual pancreatic activity (range, 17 to 667 microg/g stool) and 75 had no pancreatic activity. Children with no pancreatic activity had significantly lower coefficients of fat absorption than did those with residual pancreatic activity (81% +/- 14% versus 94% +/- 3%; P = 0.009) and significantly lower adjusted height Z score (-0.8 +/- 1.0 versus -0.1 +/- 1.3; P = 0.03). Children with residual pancreatic activity had significantly greater improvement in weight for age Z scores, upper arm muscle area Z scores, and upper arm fat area Z scores than children with no pancreatic activity (P </= 0.01). Children with no pancreatic activity were significantly (P = 0.007) more likely to have the DeltaF508/DeltaF508 genotype than were those with residual pancreatic activity (61% versus 11%).

CONCLUSIONS

These data suggest that a substantial number (12% in this sample) of children with cystic fibrosis have a misclassified pancreatic status. Children with residual FE had greater fat absorption and improved growth and nutritional status over 24 months. FE assessment should be used to verify pancreatic status in patients with cystic fibrosis.

Fecal chymotrypsin and elastase-1 determination on one single stool collected at random: diagnostic value for exocrine pancreatic status

OBJECTIVE

The secretin-cholecystokinin test is the "gold standard" to evaluate exocrine pancreatic function. But this direct duodenal intubation test is invasive, particularly in children, time-consuming, and expensive. For several years, indirect noninvasive tests of pancreatic insufficiency have been developed, such as fecal chymotrypsin (FChT) and fecal elastase-1 (FEL-1) measurements. Generally, elastase-1 is truly admitted to be the most relevant test of exocrine pancreatic status. However, so far, no consensus for stool collection protocol exists. The aim of our study was to investigate the diagnostic advantage from measuring fecal proteases in stool samples collected for two or three consecutive days in comparison to one single stool sample collected at random.

DESIGN

A total of 69 children were divided into group A (stool samples collected for three consecutive days) and group B (stool samples collected for two consecutive days). These two groups included pancreatic-sufficient patients (PS) and severe pancreatic-insufficient patients (PI). One single determination of fecal chymotrypsin activity and of fecal elastase-1 concentration was realized on each stool.

RESULTS

The same relatively important intraindividual variability of fecal proteases was observed in group A and B (mean coefficients of variation (CVs) 36% vs. 40.2% for chymotrypsin, 22.2% vs. 26.8% for elastase-1). No significant PS or severe PI diagnostic discordance was observed between 1, 2, or 3 days of stool collections.

CONCLUSION

Our study clearly shows that the determination of fecal proteases on one single stool collected at random is sufficient to evaluate pancreatic exocrine status for PS and severe PI.