Detection and follow up of exocrine pancreatic insufficiency in cystic fibrosis: a review

Pancreatic enzyme replacement therapy for people with cystic fibrosis

BACKGROUND

Most people with cystic fibrosis (CF) (80% to 90%) need pancreatic enzyme replacement therapy (PERT) to prevent malnutrition. Enzyme preparations need to be taken whenever food is taken, and the dose needs to be adjusted according to the food consumed. A systematic review on the efficacy and safety of PERT is needed to guide clinical practice, as there is variability between centres with respect to assessment of pancreatic function, time of commencing treatment, dose and choice of supplements. This is an updated version of a published review.

OBJECTIVES

To evaluate the efficacy and safety of PERT in children and adults with CF and to compare the efficacy and safety of different formulations of PERT and their appropriateness in different age groups. Also, to compare the effects of PERT in CF according to different diagnostic subgroups (e.g. different ages at introduction of therapy and different categories of pancreatic function).

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register comprising references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings. Most recent search: 07 November 2019. We also searched an ongoing trials website and the websites of the pharmaceutical companies who manufacture pancreatic enzyme replacements for any additional trials. Most recent search: 26 December 2019.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials in people of any age, with CF and receiving PERT, at any dosage and in any formulation, for a period of not less than four weeks, compared to placebo or other PERT preparations.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trials and extracted outcome data. They also assessed the risk of bias and quality of the evidence (GRADE) of the trials included in the review.

MAIN RESULTS

14 trials were included in the review (641 children and adults with CF), two of these were parallel trials and 12 were cross-over trials. Interventions included different enteric and non-enteric-coated preparations of varying formulations in comparison to each other. The number of participants in each trial varied between 14 and 129. 13 trials were for a duration of four weeks and one trial lasted seven weeks. The majority of the trials had an unclear risk of bias from the randomisation process as the details of this were not given; they also had a high risk of attrition bias and reporting bias. The quality of the evidence ranged from moderate to very low. We mostly could not combine data from the trials as they compared different formulations and the findings from individual trials provided insufficient evidence to determine the size and precision of the effects of different formulations.

AUTHORS' CONCLUSIONS

There is limited evidence of benefit from enteric-coated microspheres when compared to non-enteric coated pancreatic enzyme preparations up to one month. In the only comparison where we could combine any data, the fact that these were cross-over trials is likely to underestimate the level of inconsistency between the results of the trials due to over-inflation of CIs from the individual trials.There is no evidence on the long-term effectiveness and risks associated with PERT. There is also no evidence on the relative dosages of enzymes needed for people with different levels of severity of pancreatic insufficiency, optimum time to start treatment and variations based on differences in meals and meal sizes. There is a need for a properly designed trial that can answer these questions.

Quinolizidine alkaloids derivatives from Sophora alopecuroides Linn: Bioactivities, structure-activity relationships and preliminary molecular mechanisms

Quinolizidine alkaloids, as essential active ingredients extracted from Sophora alopecuroides Linn, have been well concerned in the past several decades owing to the unique structural features and numerous pharmacological activities. Quinolizidine alkaloids consist of matrine, oxymatrine, sophoridine, sophocarpine and aloperine etc. Additionally, quinolizidine alkaloids exert various excellent activities, including anti-cancer, anti-inflammation, anti-fibrosis, anti-virus and anti-arrhythmia regulations. In this review, we comprehensively clarify the pharmacological activities of quinolizidine alkaloids, as well as the relationship between biological function and structure-activity of substituted quinolizidine alkaloids. We believe that biological agents based on the pharmacological functions of quinolizidine alkaloids could be well applied in clinical practice.

Fecal Fat Concentration and Excretion in the First 2 Years of Life: a Cross-Sectional Study

OBJECTIVES

Data on pancreatic exocrine secretion in the youngest children are scarce. The aim of the study was to determine the range of normal values for fecal fat concentration (FFC) and fecal fat excretion (FFE) in infants and toddlers up to 2 years of age.

METHODS

A total of 160 subjects aged 1 to 24 months (8 groups of 20: aged 1-3, 4-6 months, etc) were included in the study. In all children, FFC (%) and FFE (g/day) were assessed in 3-day stool collection.

RESULTS

FFC correlated with age (r = -0.50, P < 0.0001). Of infants aged 1 to 3 months 65% had FFC higher than the <5% norm proposed for older children. The values of 90th/95th FFC percentile ranged from 9.7/13.0% at 1 month to 3.1/3.2% at 24 months. FFE did not differ between age groups. It was, however, higher than 4 and 3 g/day in 7.5% and 15.0% infants, respectively. The first detailed nomogram for the assessment of FFC and FFE in children aged 1 to 24 months was created.

CONCLUSIONS

Healthy infants may have higher FFC and FFE than older children. We provide reference values, which should allow for both precise and facile FFC and FFE interpretation in clinical practice.

Elastase as a potential biomarker for radiation-induced gut wall injury of the distal bowel in an experimental mouse model

BACKGROUND AND PURPOSE

Traditionally, elastase has been used to study exocrine activity of the pancreas in patients with chronic pancreatitis and cystic fibrosis, and calprotectin as a marker for gut-wall inflammation in patients with inflammatory bowel disease. The aim of the study was to find out whether elastase and calprotectin could be used as inflammatory markers for radiation-induced gut wall injury of the distal bowel.

MATERIAL AND METHODS

Adult male mice were exposed to two, three, or four fractions of 6 Gy or 8 Gy irradiation to the sigmoid and rectum of the large bowel, using a linear accelerator. Fecal samples were collected from mice at 1, 3, and 6 weeks post-irradiation. The fecal levels of elastase and calprotectin were analyzed using ELISA.

RESULTS

Three and 6 weeks after irradiation, we found a dose-effect relationship between dose of ionizing radiation and the fecal level of elastase; that is significantly higher levels of elastase were observed in mice that had received a high irradiation dose. We also found that irradiated mice hosted in the same cage had a comparable level (either high or low) of elastase. No significant differences were observed from the calprotectin data.

CONCLUSIONS

We found a clear association between the dose of ionizing radiation to the distal colon and the level of elastase in the fecal samples.

Pancreatic enzyme replacement therapy for people with cystic fibrosis

BACKGROUND

Most people with cystic fibrosis (80% to 90%) need pancreatic enzyme replacement therapy to prevent malnutrition. Enzyme preparations need to be taken whenever food is taken, and the dose needs to be adjusted according to the food consumed. A systematic review on the efficacy and safety of pancreatic enzyme replacement therapy is needed to guide clinical practice, as there is variability between centres with respect to assessment of pancreatic function, time of commencing treatment, dose and choice of supplements. This is an updated version of a published review.

OBJECTIVES

To evaluate the efficacy and safety of pancreatic enzyme replacement therapy in children and adults with cystic fibrosis and to compare the efficacy and safety of different formulations of this therapy and their appropriateness in different age groups. Also, to compare the effects of pancreatic enzyme replacement therapy in cystic fibrosis according to different diagnostic subgroups (e.g. different ages at introduction of therapy and different categories of pancreatic function).

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register comprising references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings. Most recent search: 15 July 2016.We also searched an ongoing trials website and the websites of the pharmaceutical companies who manufacture pancreatic enzyme replacements for any additional trials. Most recent search: 22 July 2016.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials in people of any age, with cystic fibrosis and receiving pancreatic enzyme replacement therapy, at any dosage and in any formulation, for a period of not less than four weeks, compared to placebo or other pancreatic enzyme replacement therapy preparations.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trials and extracted outcome data. They also assessed the risk of bias of the trials included in the review.

MAIN RESULTS

One parallel trial and 12 cross-over trials of children and adults with cystic fibrosis were included in the review. The number of participants in each trial varied between 14 and 129 with a total of 512 participants included in the review. All the included trials were for a duration of four weeks. The included trials had mostly an unclear risk of bias from the randomisation process as the details of this were not given; they also mostly had a high risk of attrition bias and reporting bias.We could not combine data from all the trials as they compared different formulations. Findings from individual studies provided insufficient evidence to determine the size and precision of the effects of different formulations. Ten studies reported information on the review's primary outcome (nutritional status); however, we were only able to combine data from two small cross-over studies (n = 41). The estimated gain in body weight was imprecise, 0.32 kg (95% confidence interval -0.03 to 0.67; P = 0.07). Combined data from the same studies gave statistically significant results favouring enteric-coated microspheres over enteric-coated tablets for our secondary outcomes stool frequency, mean difference -0.58 (95% confidence interval -0.85 to -0.30; P < 0.0001); proportion of days with abdominal pain, mean difference -7.96% (95% confidence interval -12.97 to -2.94; P = 0.002); and fecal fat excretion, mean difference -11.79 g (95% confidence interval -17.42 to -6.15; P < 0.0001). Data from another single small cross-over study also favoured enteric-coated microspheres over non-enteric-coated tablets with adjuvant cimetidine in terms of stool frequency, mean difference -0.70 (95% confidence interval -0.90 to -0.50; P < 0.00001).

AUTHORS' CONCLUSIONS

There is limited evidence of benefit from enteric-coated microspheres when compared to non-enteric coated pancreatic enzyme preparations up to one month. In the only comparison where we could combine any data, the fact that these were cross-over studies is likely to underestimate the level of inconsistency between the results of the studies due to over-inflation of confidence intervals from the individual studies.There is no evidence on the long-term effectiveness and risks associated with pancreatic enzyme replacement therapy. There is also no evidence on the relative dosages of enzymes needed for people with different levels of severity of pancreatic insufficiency, optimum time to start treatment and variations based on differences in meals and meal sizes. There is a need for a properly designed study that can answer these questions.

Pancreatic Elastase-1 Quick Test for rapid assessment of pancreatic status in cystic fibrosis patients

BACKGROUND

At present, fecal elastase-1 ELISA determination is the most sensitive and specific tubeless pancreatic function test available. However, the results are not available the same day in routine clinical practice. This prospective study aims at evaluating the sensitivity and specificity of the Elastase-1 Quick™ Test by comparing the results with the ELISA test.

METHODS

The study was composed of three groups: the screening-diagnosed cystic fibrosis (CF) patients (n=28), the screened, but non-CF subjects (n=36) and non-screened CF patients (n=62). Pancreatic status (normal vs abnormal) was evaluated using the Pancreas Elastase-1 Quick™ Test. Fecal elastase-1 concentration was determined with a commercially available ELISA kit, used as reference. The cut-off for abnormal results was set at <200μg/g of stool.

RESULTS

The Pancreatic Elastase-1 Quick Test™ showed the following sensitivities and specificities in the studied groups: 92.8% and 96.6% in all subjects, 90.5% and 100% in screening samples, and 92.8 and 90.5% in CF patients.

CONCLUSION

Pancreatic Elastase-1 Quick Test™ proves to be a rapid and reliable option to qualitatively evaluate pancreatic function for diagnostic purposes in a clinical setting of CF care.

Development and Diagnostic Accuracy of a Breath Test for Pancreatic Exocrine Insufficiency in Chronic Pancreatitis

OBJECTIVE

To develop a ¹³C-labeled substrate breath test by defining the optimal ¹³C-labeled substrate, substrate dose, test meal, and duration of the test and evaluating its accuracy for the diagnosis of pancreatic exocrine insufficiency (PEI) in chronic pancreatitis (CP).

METHODS

Five consecutive prospective comparative studies in patients with known advanced CP and healthy controls were performed to develop the optimal breath test. Coefficient of fat absorption was used as the reference method. The diagnostic accuracy of the optimized breath test was prospectively further evaluated in patients with advanced CP using coefficient of fat absorption as the reference method.

RESULTS

The optimal breath test protocol was that using 250 mg of ¹³C-mixed triglyceride as substrate together with a test meal containing 16 g of fat. Coefficient of fat absorption and breath test results correlated significantly (r = 0.736, P < 0.001). The test has sensitivity, specificity, and overall accuracy of 92.9%, 91.7%, and 92.3%, respectively, for the diagnosis of PEI.

CONCLUSIONS

The optimized ¹³C-mixed triglyceride breath test is an accurate and simple breath test for the diagnosis of PEI in patients with CP, easily applicable to the clinical routine.

Dual core quantum dots for highly quantitative ratiometric detection of trypsin activity in cystic fibrosis patients

We present herein two colour encoded silica nanospheres (2nanoSi) for the fluorescence quantitative ratiometric determination of trypsin in humans. Current detection methods for cystic fibrosis diagnosis are slow, costly and suffer from false positives. The 2nanoSi proved to be a highly sensitive, fast (minutes), and single-step approach nanosensor for the screening and diagnosis of cystic fibrosis, allowing the quantification of trypsin concentrations in a wide range relevant for clinical applications (25-350 μg L(-1)). Furthermore, as trypsin is directly related to the development of cystic fibrosis (CF), different human genotypes, i.e. CF homozygotic, CF heterozygotic, and unaffected, respectively, can be determined using our 2nanoSi nanospheres. We anticipate the 2nanoSi system to be a starting point for non-invasive, easy-to-use and cost effective ratiometric fluorescent biomarkers for recessive genetic diseases like human cystic fibrosis. In a screening program in which the goal is to detect disease and also the carrier status, early diagnosis could be of great help.

Pancreatic enzyme replacement therapy for people with cystic fibrosis

BACKGROUND

Most people with cystic fibrosis (80% to 90%) need pancreatic enzyme replacement therapy to prevent malnutrition. Enzyme preparations need to be taken whenever food is taken, and the dose needs to be adjusted according to the food consumed. A systematic review on the efficacy and safety of pancreatic enzyme replacement therapy is needed to guide clinical practice, as there is variability between centres with respect to assessment of pancreatic function, time of commencing treatment, dose and choice of supplements.

OBJECTIVES

To evaluate the efficacy and safety of pancreatic enzyme replacement therapy in children and adults with cystic fibrosis and to compare the efficacy and safety of different formulations of this therapy and their appropriateness in different age groups. Also, to compare the effects of pancreatic enzyme replacement therapy in cystic fibrosis according to different diagnostic subgroups (e.g. different ages at introduction of therapy and different categories of pancreatic function).

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register comprising references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings. Most recent search: 14 August 2014.We also searched an ongoing trials website and the websites of the pharmaceutical companies who manufacture pancreatic enzyme replacements for any additional trials. Most recent search: 12 May 2014.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials in people of any age, with cystic fibrosis and receiving pancreatic enzyme replacement therapy, at any dosage and in any formulation, for a period of not less than four weeks, compared to placebo or other pancreatic enzyme replacement therapy preparations.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trials and extracted outcome data. They also assessed the risk of bias of the trials included in the review.

MAIN RESULTS

One parallel trial and 11 cross-over trials of children and adults with cystic fibrosis were included in the review. The number of participants in each trial varied between 14 and 129 with a total of 426 participants included in the review. All the included trials were for a duration of four weeks. The included trials had mostly an unclear risk of bias from the randomisation process as the details of this were not given; they also mostly had a high risk of attrition bias and reporting bias.We could not combine data from all the trials as they compared different formulations. Findings from individual studies provided insufficient evidence to determine the size and precision of the effects of different formulations. Ten studies reported information on the review's primary outcome (nutritional status); however, we were only able to combine data from two small cross-over studies (n = 41). The estimated gain in body weight was imprecise, 0.32 kg (95% confidence interval -0.03 to 0.67, P = 0.07). Combined data from the same studies gave statistically significant results favouring enteric-coated microspheres over enteric-coated tablets for our secondary outcomes stool frequency, abdominal pain and fecal fat excretion. Data from another single small cross-over study also favoured enteric-coated microspheres over non-enteric-coated tablets with adjuvant cimetidine in terms of stool frequency.

AUTHORS' CONCLUSIONS

There is limited evidence of benefit from enteric-coated microspheres when compared to non-enteric coated pancreatic enzyme preparations up to one month. In the only comparison where we could combine any data, the fact that these were cross-over studies is likely to underestimate the level of inconsistency between the results of the studies due to over-inflation of confidence intervals from the individual studies.There is no evidence on the long-term effectiveness and risks associated with pancreatic enzyme replacement therapy. There is also no evidence on the relative dosages of enzymes needed for people with different levels of severity of pancreatic insufficiency, optimum time to start treatment and variations based on differences in meals and meal sizes. There is a need for a properly designed trial that can answer these questions.

High serum retinol and lung function in young patients with cystic fibrosis

OBJECTIVE

The aim of the present study was to explore the relation between lung function and serum retinol (SR) in cystic fibrosis (CF) patients.

METHODS

This was a cross-sectional study conducted in a group of 98 young patients with CF (6.8-22.3 years), after the exclusion of those with pulmonary exacerbation, vitamin A deficiency, or other risks, from an initial group of 124 cases.

RESULTS

Data of forced expiratory volume in 1 second (FEV₁) were widely scattered (87.7% ± 16.9%). These were similar in the 78 pancreatic insufficient and 11 pancreatic sufficient patients. SR (56.6 ± 18.4 μg/dL) was >2.5th percentile of healthy people in the whole group, although 31 patients were situated above the 97.5th percentile (higher value: 110 μg/dL). The FEV₁ was noticeably higher in these than in those within the normal range (93.6 ± 14.0 vs 85.0 ± 17.6 μg/dL; P < 0.05). The z score of SR correlated positively with FEV₁ (r = 0.364; P = 0.000), after adjusting data for sex, age, body mass index, and pancreatic function. The odds ratio for a FEV₁ >80% is 3.78 in patients with SR above the 97.5th percentile, versus only 0.26 in those within the normal range. There were no cases with retinol toxicity.

CONCLUSIONS

FEV₁ of young patients with CF correlates positively with SR, regardless of age, pancreatic function, or nutritional condition. Those with a moderately high retinol (up to 110 μg/dL) maintain the best respiratory function (FEV₁ ≥80% in >90% of them) without any signs of toxicity.

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.

Clinical phenotype of cystic fibrosis patients with the G551D mutation

BACKGROUND

Data on whether the phenotype of cystic fibrosis (CF) patients with compound heterozygocity for G551D (Gly551Asp) differs from patients with F508del (Phe508del) homozygous mutations is divergent.

AIM

We hypothesized that CF patients with the G551D mutation would have less severe disease than F508del homozygotes.

DESIGN

We compared the clinical phenotype of adult patients with a G551D mutation with adult patients homozygous for F508del and those with the missense mutation R117H (Arg117His). Compound heterozygotes for the G551D and R117H were analysed separately.

METHODS

Data were collected for 101 adult CF patients. Group 1-4 represents in order F508del homozygote patients (n = 61), those with the G551D mutation and a more severe mutation (n = 13), those with R117H mutation and a more severe mutation (n = 23) and also those compound for both the R117H and G551D mutations (n = 4).

RESULTS

Our findings have shown that adult patients with the G551D mutation and a second severe mutation have a milder clinical phenotype than F508del homozygous adult patients. Higher FEV(1) and body mass index and less impaired glucose tolerance was demonstrated in the patients with G551D and R117H compared to F508del homozygotes. There was a reduced yearly rate of decline of FEV(1) (P < 0.05), infection with Pseudomonas aeruginosa along with reduced burden of care. Compound heterozygosity for G551D and R117H mutations was associated with normal spirometry, body mass index, no chronic infection and no symptoms.

CONCLUSION

Mutations on different chromosomes are not independent of each other for the overall impact on the amount of functional CFTR. This study suggests that patients with the G551D mutation and a second severe mutation have a milder clinical phenotype than F508del homozygous patients, but the phenotype is not as mild as patients with the R117H mutation.

[Cystic fibrosis: review]

Cystic Fibrosis (CF) is the recessive autossomic disease more frequent in the caucasian race. The main characteristic is a mutation in CFTR, a trans-membranar protein, responsible for chlorates transportation. This protein has a diffuse epithelial distribution, which gives a multissistemic involvement to this disease, with clinical manifestations with variable degrees of severity. The development of better health care associated with new therapeutic options became responsible for an increase of survival, so CF is no longer a paediatric disease. Lung transplantation also has an important role, bringing new treatment perspectives. So, this pathology has an increased multi-disciplinary involvement in which the pulmonologist have a preponderant role.

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.

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.

Variability of fecal pancreatic elastase measurements in cystic fibrosis patients

BACKGROUND

the fecal pancreatic elastase-1 (EL-1) test is a new non-invasive test for pancreatic function. The aim of the study was to evaluate the intra-patient variability of the fecal EL-1 test in a cystic fibrosis (CF) population.

METHODS

26 CF patients were recruited. Mean patient (S.D.) age was 13.7 years (5.39). Nineteen patients had classical pancreatic insufficiency (PI) based on a clinical syndrome of malabsorption plus steatorrhea on a 72 h fecal fat balance. They were all treated with enzyme supplements. Four patients had classical pancreatic sufficiency (PS): no symptoms of malabsorption, no steatorrhea on a 72 h fecal fat balance, no enzyme treatment. Two patients had symptoms suggestive of PI but had a normal 72 h fecal fat balance: (doubtful pancreatic status (PD)). The CF patients were asked to collect stool samples on 7 consecutive days. EL-1 content in the samples was measured in duplicate. A cut-off of 200 microgEL-1/g stool was used for diagnosing PI.

RESULTS

mean intra-assay variability was 4.06%. All PI patients had EL-1 levels below detection limit. For the PS group maximal intra-patient variability was 35%, one stool sample EL-1 level was below the 200-microg cut-off. In the PD group the maximal intra-patient variability was 37% and EL-1 levels were inconclusive for the diagnosis of PI in both patients.

CONCLUSIONS

the EL-1 test can be used for diagnosing severe PI in CF patients with overt clinical symptoms of malabsorption. However, in CF patients where the clinical picture is less clear the EL-1 test may be inconclusive due to significant intra-patient variability.

Faecal elastase-1 test is superior to faecal lipase test in the assessment of exocrine pancreatic function in cystic fibrosis

BACKGROUND AND AIMS

Direct tests are characterized by the highest sensitivity and specificity. However, their practical use, especially in children, is limited. Among the indirect tests, the highest sensitivity and specificity was documented for faecal elastase-1 test, yet the value of faecal lipase test in cystic fibrosis (CF) has not been defined. Therefore, the aim of the present study was to compare the sensitivity and the specificity of the faecal lipase test to the faecal elastase-1 test in the assessment of exocrine pancreatic function in children with CF.

METHODS

The study comprised 90 CF patients and 95 healthy subjects (HS). In all subjects, faecal elastase-1 concentrations (ELISA) and lipase activities (ELISA) were measured. The presence of pancreatic insufficiency was documented by the determination of faecal fat excretion in 78 pancreatic insufficient and by the secretin-cholecystokinin test in 12 CF patients without steatorrhoea. Sensitivity and specificity of the faecal elastase-1 test and faecal lipase test were analysed and, in 50 HS, sample-to-sample and day-to-day variations were determined.

RESULTS

With cut-off levels providing the same specificity for both tests (95.8%), the sensitivity of the faecal elastase-1 test (91.1%) was significantly higher (p < 0.0036) than that of the faecal lipase test (76.7%). Sample-to-sample (mean +/- SEM: 13.2 +/- 1.2% vs 23.4 +/- 2.2%) and day-to-day variations (mean +/- SEM: 16.3 +/- 1.2% vs 32.5 +/- 2.6%) were significantly lower (p < 0.0001) for elastase-1 than for lipase measurements.

CONCLUSION

Among indirect tests, faecal elastase-1 test is superior to faecal lipase test in the assessment of exocrine pancreatic function in cystic fibrosis.

Fecal elastase-1 cut-off levels in the assessment of exocrine pancreatic function in cystic fibrosis

BACKGROUND

Fecal elastase-1 (E1) test is a sensitive and specific indirect test. However, there are few data on the best cut-off level in the assessment of exocrine pancreatic function in cystic fibrosis (CF).

MATERIAL AND METHODS

In 725 CF patients and 243 healthy subjects (HS) from Greece, Russia, Poland and the United Kingdom, E1 concentrations were measured. The best cut-off levels for the discrimination between CF and HS (for whole group as well as for individual countries) were calculated.

RESULTS

The best cut-off level for the differentiation between CF pancreatic insufficiency and normal pancreatic function in HS was found to be 184 microg/g of feces. However, some inter-country differences were stated. E1 concentrations in the UK subgroup were significantly lower than those found in Polish and Russian CF patients. E1 concentrations in Greek patients were significantly higher than in the other countries. However, E1 concentrations in Delta F508 homozygotes were very similar in all studied subgroups.

IN CONCLUSION

In clinical practice, instead of a single best cut-off level for the E1 test, we suggest using a range of values (160-200 microg/g). The presence of different best cut-off levels within countries is a practical consequence of the different distribution of pancreatic function.

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

OBJECTIVE

Exocrine pancreatic function in patients with cystic fibrosis (CF) can be evaluated by direct and indirect tests. In pediatric patients, indirect tests are preferred because of their less invasive character, especially in CF patients with respiratory disease. Fecal tests are noninvasive and have been shown to have a high sensitivity and specificity. However, there is no comparative study in CF patients. Therefore, the aim of the present study was to compare the sensitivity and the specificity of the fecal elastase-1 (E1) test with the fecal chymotrypsin (ChT) test in a large cohort of CF patients and healthy subjects (HS).

DESIGN

One hundred twenty-three CF patients and 105 HS were evaluated. In all subjects, E1 concentration and ChT activity were measured. In the CF group, fecal fat excretion was also determined. The sensitivity and specificity of the fecal E1 test and ChT test were compared.

RESULTS

With a cutoff level of 3 U/g, ChT specificity in HS was similar to that of E1, but E1 sensitivity in CF patients was significantly higher (90.2% vs 81.3%). With a cutoff level of 6 U/g, ChT and E1 sensitivity in CF patients was identical, but E1 specificity in HS was again significantly higher (98.1% vs 90.5%). In all CF patients with severe steatorrhea (>15 g/d), E1 concentrations were abnormal and ChT activity was lower than 3 U/g. In contrast, in pancreatic-sufficient patients and patients with mild steatorrhea (< or =15 g/d), the E1 sensitivity was significantly higher compared with ChT (69.2% vs 41.0%).

CONCLUSIONS

The fecal E1 test is superior to fecal ChT determination in the assessment of CF pancreatic involvement in pancreatic-sufficient patients and those patients with mild steatorrhea.