The architecture of diagnostic research: from bench to bedside--research guidelines using liver stiffness as an example

The diagnostic research process can be divided into five phases, designed to establish the clinical utility of a new diagnostic test--the index test. The aim of the present review is to illustrate the study designs that are appropriate for each diagnostic phase, using clinical examples regarding liver fibrosis diagnosed with transient elastography, when possible. Phase 0 is the preclinical pilot phase during which the validity, reliability, and reproducibility of the index test are assessed in healthy and diseased people. Phase I is designed to describe the distribution of the index test results in healthy people and its normal values. Phase IIA comprises studies designed to estimate the accuracy (sensitivity and specificity) of the index test in discriminating between diseased and nondiseased people in a clinically relevant population. Phase IIB studies allow the comparison of the accuracy of different index tests; Phase IIC studies aim to evaluate the possible harms of incorporating the index test in a diagnostic-therapeutic strategy. In phase III, diagnostic test-therapeutic randomized clinical trials aim to assess the benefits and harms of the new diagnostic-therapeutic strategy versus the present strategy. Phase IV comprises large surveillance cohort studies that aim to assess the effectiveness of the new diagnostic-therapeutic strategy in clinical practice.

CONCLUSION

As common in clinical research, giving excessive weight to the results of single studies and trials is likely to divert from the totality of evidence obtained through the systematic reviews of these studies, conducted with rigorous methodology and statistical methods. (Hepatology 2014;60:408-418).

Rapid air infusion into the oesophagus: Motor response in patients with achalasia and nonobstructive dysphagia assessed with high-resolution manometry

BACKGROUND

Achalasia is a neurodegenerative disorder of the oesophagus. Alteration of motor activity induced by oesophageal distension has not been explored.

OBJECTIVES

To investigate this function, using high-resolution Manometry.

METHODS

This study enrolled 15 healthy subjects, 15 nonobstructive dysphagia (NOD), and 18 achalasia patients successfully treated with pneumatic dilation (six with restored peristalsis). The three groups underwent five rapid (<1 s) intraoesophageal infusions of 20-ml air boluses, followed by eight 5-ml water swallows.

RESULTS

WHEREAS THE RESPONSE RATE TO WATER SWALLOWS WAS SIMILAR IN THE THREE GROUPS, AIR INFUSION INDUCED A LOWER RESPONSE RATE IN ACHALASIA (MEDIAN, INTERQUARTILE RANGE: 70%, 40-100%) and, to a lesser extent, in NOD patients (100%, 60-100%) than in healthy subjects (100%, 100-100%; p < 0.001 and p = 0.06, respectively). However, the response rate was highly variable in achalasia patients irrespective of presence of peristalsis. Furthermore, the strength of motor response to air infusion when compared to water swallows was diminished in achalasia patients but not in healthy subjects and NOD.

CONCLUSIONS

Motor response to rapid air infusion was variably impaired in achalasia. The role of this alteration in the long-term outcome deserves evaluation.

Prospective evaluation of early endoscopic ultrasonography for triage in suspected choledocholithiasis: results from a large single centre series

BACKGROUND

Endoscopic ultrasonography is accurate, safe, and cost-effective in diagnosing common bile duct stones, thus suggesting the possibility to avoid invasive endoscopic retrograde cholangiopancreatography.

AIM

To prospectively evaluate the diagnostic and therapeutic performance of early endoscopic ultrasonography in suspected choledocholithiasis.

PATIENTS AND METHODS

All consecutive patients presenting to the Emergency Department with suspicion of choledocholithiasis between January 2010 and January 2012 were evaluated and categorized as low, moderate, or high probability of choledocholithiasis, according to accepted criteria. Endoscopic endosonography was carried out within 48 h from the admission and endoscopic retrograde cholangiopancreatography was performed soon in case of confirmed choledocholithiasis.

RESULTS

Overall 179 patients were included: 48 (26.8%) were classified as low, 65 (36.3%) as moderate, and 66 (36.9%) as high probability of choledocholithiasis. Of the 86 patients with common bile duct stones at endoscopic endosonography, endoscopic retrograde cholangiopancreatography confirmed the finding in 79 (92%). By multivariate analysis only the common bile duct diameter proved an independent predictor of common bile duct stones.

CONCLUSIONS

Early endoscopic endosonography is accurate in identifying choledocholithiasis allowing immediate endoscopic treatment and significant spare of unnecessary endoscopic retrograde cholangiopancreatography. This approach can be useful as a triage test to select patients not needing endoscopic retrograde cholangiopancreatography, allowing, in selected cases, their early discharge.

Feasibility and reproducibility of spleen transient elastography and its role in combination with liver transient elastography for predicting the severity of chronic viral hepatitis

Liver transient elastography (L-TE) is a reliable, noninvasive predictor of disease severity in chronic liver disease of viral aetiology (CLD). Owing to the relationships among severity of CLD, portal hypertension and spleen involvement, the assessment of splenic stiffness (S-TE) may have an added value in staging CLD. Of 132 CLD patients of viral aetiology, 48 with myeloproliferative disorders (MD) and 64 healthy volunteers (HV), were concurrently investigated by both L-TE and S-TE. Liver disease severity was staged by liver biopsy (LB; Metavir) taken concurrently with TE examination and upper gastrointestinal tract endoscopy for gastro-oesophageal varices. The S-TE inter-observer agreement was analysed by an intra-class correlation coefficient (ICC); L-TE and S-TE accuracy was evaluated by receiver operating characteristic (ROC) curve analysis. Logistic regression analysis assessed the independent effect of L-TE and S-TE as predictors of hepatic fibrosis stage. S-TE failed in 22 CLD (16.6%), 12 (25%) MD and 12 (18%) HV. In the three groups, the ICC was 0.89 (0.84-0.92), 0.90 (0.85-0.94) and 0.86(0.80-0.91), respectively. In the CLD group, L-TE and S-TE independently predicted significant fibrosis (OR 5.2 and 4.6) and cirrhosis (OR 7.8 and 9.1), but at variance from L-TE, S-TE was independent from liver necroinflammation and steatosis. The NPV of S-TE for gastro-oesophageal varices was 100% using a 48 kPa cut-off. In CLD, spleen stiffness alone or in combination with hepatic stiffness can be reliably and reproducibly assessed by TE with the added value of improving the noninvasive diagnosis of severe liver disease and excluding the presence of oesophageal varices.

Chromogranin A in diagnosing and monitoring patients with gastroenteropancreatic neuroendocrine neoplasms: a large series from a single institution

BACKGROUND/AIMS

Plasma chromogranin A (CgA) is the most widely used biochemical biomarker in the diagnostic workup and follow-up of gastroenteropancreatic neuroendo- crine neoplasms (GEP-NENs). Herein, we assessed the clinical utility of CgA in diagnosing and monitoring a large series of GEP-NENs.

PATIENTS AND METHODS

A total of 181 GEP-NEN patients (87 males, 94 females) with pancreatic (n = 81) and gastrointestinal neoplasms (n = 100) were included; 99 patients had grade (G)1 NENs (Ki-67 ≤2%), 57 G2 NENs (Ki-67 3-20%) and 25 G3 NENs (Ki-67 >20%); 81 patients had tumor-node-metastasis (TNM) stage I, 14 stage II, 17 stage III and 69 stage IV cancer. For every patient, CgA values were assessed at diagnosis and during follow-up.

RESULTS

At diagnosis, the CgA values were above the upper reference limit in 148 patients (82%); the median CgA levels were significantly higher in functioning than in nonfunctioning tumors (295 vs. 43 U/l; p = 0.0001) as well as significantly higher in patients with metastases than in those without metastases (324.5 vs. 42 U/l; p = 0.0001). In logistic regression analysis, baseline CgA levels were significantly associated with Ki-67 index (p < 0.0001) and TNM stage (p < 0.0001) independently of the age and sex of the patient and the primary site of the tumor. The overall 5- and 10-year survival rates were 74 and 64.5%, respectively. A low Ki-67 index, the type of treatment and an early CgA decrease after treatment were positively correlated with the survival rate. After radical surgery, 15/95 patients relapsed, and an increase in CgA values anticipated the clinical and objective disease recurrence after a period of 9-12 months.

CONCLUSIONS

In GEP-NENs, plasma CgA has a significant prognostic relevance.

Effect of Cold Water on Esophageal Motility in Patients With Achalasia and Non-obstructive Dysphagia: A High-resolution Manometry Study

Background/Aims

Swallowing of cold liquids decreases amplitude and velocity of peristalsis in healthy subjects, using standard manometry. Patients with achalasia and non obstructive dysphagia may have degeneration of sensory neural pathways, affecting motor response to cooling. To elucidate this point, we used high-resolution manometry.

Methods

Fifteen healthy subjects, 15 non-obstructive dysphagia and 15 achalasia patients, after pneumatic dilation, were studied. The 3 groups underwent eight 5 mL single swallows, two 20 mL multiple rapid swallows and 50 mL intraesophageal water infusion (1 mL/sec), using both water at room temperature and cold water, in a randomized order.

Results

In healthy subjects, cold water reduced distal contractile integral in comparison with water at room temperature during single swallows, multiple rapid swallows and intraesophageal infusion (ratio cold/room temperature being 0.67 [95% CI, 0.48-0.85], 0.56 [95% CI, 0.19-0.92] and 0.24 [95% CI, 0.12-0.37], respectively). A similar effect was seen in non-obstructive dysphagia patients (0.68 [95% CI, 0.51-0.84], 0.69 [95% CI, 0.40-0.97] and 0.48 [95% CI, 0.20-0.76], respectively), whereas no changes occurred in achalasia patients (1.06 [95% CI, 0.83-1.29], 1.05 [95% CI, 0.77-1.33] and 1.41 [95% CI, 0.84-2.00], respectively).

Conclusions

Our data suggest impairment of esophageal reflexes induced by cold water in patients with achalasia, but not in those with non obstructive dysphagia.

Defensive medicine practices among gastroenterologists in Lombardy: between lawsuits and the economic crisis

BACKGROUND

Defensive medicine is becoming more frequent behaviour and has an impact on the economic 'health' of national healthcare systems.

AIM

The aim of this study was to clarify the impact of defensive medicine on gastroenterological practices in Lombardy.

METHODS

Gastroenterologists attending the Lombardy Annual Gastroenterological Conference received a questionnaire based on multiple choice tests and visual analogue scales. The questionnaire was divided into three parts evaluating the respondent's characteristics, the number of procedures prescribed, and the percentage of those performed with a defensive purpose.

RESULTS

Sixty-four of 107 participants (60%) completed the questionnaire, 94% of whom reported practising defensive medicine. The percentage of defensively requested procedures amounted to 18% of all digestive endoscopies, 8.9% of abdominal ultrasonography scans, 4.9% of abdominal computed tomography or magnetic resonance scans, and 12.2% of all consultations. The total number of defensive procedures prescribed per month by the participants was 878, and 31.7% of the performed procedures (n=4897) were reported to defensively based. On the basis of the 2012 regional reimbursement fees, the yearly cost of defensive procedures prescribed and/or performed by all gastroenterologists in Lombardy was estimated to be € 8,637,835.

CONCLUSIONS

Our findings indicate that defensive medicine profoundly affects current medical practices among gastroenterologists, and has a considerable economic impact.

Chronic autoimmune atrophic gastritis associated with primary hyperparathyroidism: a transversal prospective study

DESIGN

The coexistence of chronic autoimmune atrophic gastritis (CAAG) and primary hyperparathyroidism (PHPT) has been described previously, even if its extent and underlying mechanisms remain poorly understood. We therefore prospectively evaluated this association in two series of patients, one with CAAG and the other with sporadic PHPT.

METHODS

From January 2005 to March 2012, 107 histologically confirmed CAAG patients and 149 PHPT patients were consecutively enrolled. Routine laboratory assays included serum calcium, parathyroid hormone (PTH), plasma gastrin and chromogranin A (CgA). In CAAG patients with high PTH levels, ionized calcium and 25(OH)-vitamin D were evaluated. All CAAG and hypergastrinemic PHPT patients received an upper gastrointestinal endoscopy. Exclusion criteria were familial PHPT, MEN1 syndrome, treatment with proton pump inhibitor drugs, Helicobacter pylori infection and renal failure.

RESULTS

Of the 107 CAAG patients, nine (8.4%) had PHPT and 13 (12.1%) had secondary hyperparathyroidism stemming from vitamin D deficiency. Among the 149 PHPT patients, 11 (7.4%) had CAAG. Gastrin and CgA levels were similar in the CAAG patients with vs those without hyperparathyroidism (either primary or secondary), and calcium and PTH levels were similar in the PHPT patients with vs those without CAAG.

CONCLUSIONS

This study confirms a non-casual association between PHPT and CAAG. The prevalence of PHPT in CAAG patients is threefold that of the general population (8.4 vs 1-3%), and the prevalence of CAAG in PHPT patients is fourfold that of the general population (7.4 vs 2%). The mechanisms underlying this association remain unknown, but a potential role for autoimmunity is suggested.

Extracellular matrix proteins and displacement of cultured fibroblasts from duodenal biopsies in celiac patients and controls

BACKGROUND

Celiac disease (CD) is mainly characterised by villous atrophy and mucosal architectural rearrangement. The fibroblasts (FBs) are the most abundant mesenchymal cell type in the intestinal mucosa and are responsible for both the architectural arrangement of the villi and the formation of the extracellular matrix (ECM). This study aimed at the evaluation of both the intracellular distribution of different proteins involved in ECM and FBs characterisation, and the cellular displacement of primary FBs obtained from duodenal endoscopic biopsies of healthy subjects and celiac patients.

METHODS

Primary healthy and celiac duodenal FBs were evaluated by means of immuno-fluorescence assay for collagen type I and IV, fibronectin, actin, alpha-Smooth Muscle Actin (alpha-SMA), Fibroblast Surface Protein (FSP) and transglutaminase type 2 (TG2). The geometric indexes of the fluorescence signals were investigated by image analysis software (Image J, NIH). Both morphology and kinetic were evaluated during a 72 hours time course movie. TG2 medium activity was evaluated by means of ELISA.

RESULTS

All the cells examined were immunopositive for FSP, alpha-SMA, actin, collagen I, collagen IV and TG2. CD cells showed a signet collagen-I and collagen-IV pattern, as compared to the controls being characterised by a spindle geometry. Moreover, the collagen signals in CD FBs showed a significantly higher circularity index (major orthogonal diameter ratio) than the controls (p<0.0001), whereas the perimeter and area ratio were significantly lower (p<0.0001). The TG2 signal had a decreased area (p<0.05), but a two-fold increased medium activity. The time course highlighted a reduction of the displacement of CD FBs.

CONCLUSIONS

The isolated primary CD FBs showed a different collagen and TG2 pattern of distribution associated with a different cellular displacement. The reasons for such CD cell peculiar characteristics are yet unknown but they might represent a factor in the progression of the intestinal damage.

Nutritional deficiencies in inflammatory bowel disease: therapeutic approaches

BACKGROUND & AIMS

Malnutrition is common in inflammatory bowel diseases (IBD), mainly in Crohn's disease (CD) because the small bowel is primarily affected. We reviewed the literature to highlight the importance of proper nutrition management.

METHODS

A PubMed search was performed for English-language publications from 1999 through 2012. Manuscripts comparing nutritional approaches for IBD patients were selected.

RESULTS

We identified 2025 manuscripts: six meta-analyses, 170 clinical-trials, 692 reviews. The study findings are discordant. In adult CD, enteral nutrition plays a supportive role, steroid therapy remaining the first choice treatment. In CD children enteral nutrition may represent the primary therapy. As regards parenteral nutrition, there are no large randomized studies, although mild improvements in morbidity have been described as a result of parenteral nutrition in malnourished surgical IBD patients. Specific micronutrient deficiencies are common in IBD. A number of factors may contribute to micronutrient deficiencies, and these include: dietary restriction, disease activity and surgery. The possible therapeutic roles of omega-3 fatty-acids, probiotics and prebiotics have been studied, but the results are still preliminary.

CONCLUSION

Protein-energy malnutrition and micronutrient depletion are clinical concerns in IBD patients. Enteral nutrition, parenteral nutrition and micronutrient supplementation are cornerstone of the multidisciplinary management of IBD patients.

Can we improve the detection rate and interobserver agreement in capsule endoscopy?

BACKGROUND

Data about strategies for improving the diagnostic ability of capsule endoscopy readers are lacking.

AIM

(1) To evaluate the detection rate and the interobserver agreement among readers with different experience; (2) to verify the impact of a specific training (hands-on training plus expert tutorial) on these parameters.

METHODS

17 readers reviewed 12 videos twice; between the two readings they underwent the training. The identified small bowel findings were described by a simplified version of Structured Terminology and classifies as clinically significant/non-significant. Findings identified by the readers were compared with those identified by three experts (Reference Standard).

RESULTS

The Reference Standard identified 26 clinically significant findings. The mean detection rate of overall readers for significant findings was low (about 50%) and did not change after the training (46.2% and 46.4%, respectively). There was no difference in the detection rate among readers with different experience. The interobserver agreement with the Reference Standard in describing significant findings was moderate (k = 0.44; CI95%: 0.39-0.50) and did not change after the training (k = 0.44; CI95%: 0.38-0.49) or stratifying readers according to their experience.

CONCLUSIONS

Both the interobserver agreement and the detection rate of significant findings are low, regardless of the readers' experience. Our training did not significantly increase the performance of readers with different experience.

Evaluation of hands-on training in colonoscopy: is a computer-based simulator useful?

BACKGROUND AND AIMS

The advantages of using a computer-based simulator during colonoscopy training are debated. We aimed to explore its usefulness in objectively measuring trainees' competence in colonoscopy.

METHODS

Twelve colonoscopy trainees (fully trained in upper GI endoscopy) were evaluated using a computer-based simulator (GI-Mentor, Symbionix) before and during hands-on training (i.e. after 60 colonoscopies); the controls were 15 experts (>90% of caecal intubation). Both trainees and experts performed two "screening" simulations (easy and difficult) in a randomised order, and the time to reach the caecum and withdrawal time was assessed.

RESULTS

The percentage of caecal intubation progressively increased during hands-on training. All of the trainees intubated the caecum during the easy and difficult simulations, both before and during hands-on training. The median time (interquartile range) to reach the caecum upon easy simulation was the only variable influenced by hands-on training: 2.7 min (2.1-3.2) before and 1.9 min (1.6-2) during training (p<0.01). Withdrawal time was ≥6 min in the case of five trainees before training, and three during hands-on training. Computer-based simulator performance did not correlate with hands-on training performance.

CONCLUSIONS

The computer-based simulator was not found to be useful in evaluating competence during hands-on training in colonoscopy.

Transient elastography in patients with celiac disease: a noninvasive method to detect liver involvement associated with celiac disease

BACKGROUND

Liver involvement in celiac disease (CD) is clinically relevant and could require specific treatment in addition to gluten-free diet (GFD). Transient elastography (TE), a noninvasive tool for assessing liver stiffness (LS), has widely been reported as an accurate surrogate marker of liver fibrosis.

AIMS

To prospectively identify celiac patients with liver involvement by TE and to assess the effect of GFD.

MATERIAL AND METHODS

Ninety-five histologically confirmed CD patients (24 newly diagnosed) were consecutively evaluated by TE and compared with 146 patients with chronic hepatitis C (HCV) and 54 healthy subjects.

RESULTS

LS ranged between 2.8 and 6.7 kPa (median 4.9) in healthy subjects, defining 6.9 kPa as the upper reference limit (2 SD above the mean levels). TE was above 6.9 kPa in 10 (10.5%) CD patients. Median TE values resulted significantly higher in CD patients with hypertransaminasemia than those without [6.1 vs. 4.2 kPa (p < 0.01)]. Among the 24 newly diagnosed patients with CD, median TE values declined from 4.4 to 4 kPa, after 6 months of GFD, resulting below 6.9 kPa in 100% of the patients.

CONCLUSIONS

A subset of CD patients with hypertransaminasemia showed liver involvement by TE. Accordingly, based on its accuracy in predicting liver fibrosis, TE could be used to identify those CD patients suitable for liver biopsy.

Meta-analysis: nonsteroidal anti-inflammatory drugs in biliary colic

BACKGROUND

Biliary colic is a common manifestation of cholelithiasis, developing in about one-third of patients. Even if nonsteroid anti-inflammatory drugs (NSAIDs) have widely been used to relieve biliary pain, there is a lack of systematic review of treatments on this issue.

AIM

To assess the potential benefits in terms of both pain control and reduction of complications, and the potential harms of NSAIDs in patients with biliary colic.

METHODS

Data from randomised clinical trials (RCTs) comparing NSAIDs with no treatment, placebo or other drugs in patients with biliary colic, were collected from Medline and Embase. The outcome measures were expressed as odds ratio and relative risk and then pooled using fixed or random-effect models.

RESULTS

Eleven RCTs involving 1076 subjects (268 men, 808 women; 18-86 years), including 442 controls were analysed. In comparison with placebo, NSAIDs led to a significantly higher proportion of patients with complete pain relief (RR 3.77, 95%CI 1.65-8.61; I(2) : 73%) and a significantly lower rate of complications (RR 0.53, 95% CI 0.31-0.89; I(2) : 35%). In comparison with other drugs, NSAIDs were more efficacious in controlling pain than spasmolytics (RR 1.47, 95% CI 1.03-2.10; I(2) : 55%); there was no difference between NSAIDs and opioids (RR 1.05, 95% CI 0.82-1.33; I(2) : 74%).

CONCLUSIONS

In patients with biliary colic NSAIDs are the first-choice treatments as they control pain with the same efficacy of opioids and significantly reduce the proportion of patients with severe complications. However, the lack of high-quality RCTs and the presence of consistent heterogeneity among studies may partially flaw these results.

Applicability of a new robotic walking aid in a patient with cerebral palsy. Case report

BACKGROUND

Gait training with the help of assistive technological devices is an innovative field of research in neurological rehabilitation. Most of the available gait training devices do not allow free movement in the environment, which would be the most suitable natural and motivating condition for training children with neurological gait impairment.

AIM

To evaluate the potential applicability of a new robotic walking aid as a tool for gait training in non-ambulatory children with Cerebral Palsy.

DESIGN

Single case study

SETTING

Outpatient regimen

POPULATION

A 11-years-old child unable to stand and walk independently as a result of spastic tetraplegic cerebral palsy (CP).

METHODS

The experimental device was a newly actuated version of a dynamic combined walking and standing aid (NF-Walker®) available in the market which was modified by means of two pneumatic artificial muscles driven by a foot-switch inserted in the shoes. The child was tested at baseline (while maintaining the standing position aided by the non-actuated NF-Walker®) and in the experimental condition (while using the actuated robotic aid). The outcome measures were: 2-minute walking test, 10-metre walking test, respiratory and heart parameters, energy cost of locomotion.

RESULTS

At baseline, the child was unable to perform any autonomous form of locomotion. When assisted by the actuated aid (i.e. during the experimental condition), the child was successful in moving around in his environment. His performance was 19.63 m in the 2-minute walking test and 64 s in the 10-metre walking test. Respiratory and heart parameters were higher than healthy age-matched children both at baseline and in the experimental condition. The energy cost of gait, which was not valuable in the baseline condition, was significantly higher than normality during the experimental condition.

CONCLUSION

The new robotic walking aid may help children suffering from CP with severe impairment of gait to move around in their environment.

CLINICAL REHABILITATION IMPACT

This new robotic walking device may have a potential impact in stimulating the development and in training of gait in children with neurological gait impairment. Future studies are warranted in order to test this hypothesis.

Severe chronic diarrhea and maculopapular rash: A case report

Systemic mastocytosis (SM) is a heterogeneous disease of the bone marrow characterized by abnormal growth, accumulation and activation of clonal mast cells (MCs). We report a case of SM with multi-organ involvement. A 30-year-old man presented with diarrhea, flushing, maculopapular rash with itching and weight loss. The upper and lower gastrointestinal endoscopies showed macroscopic involvement of stomach and duodenum; mucosal samples from stomach, duodenum, colon and distal ileum showed mucosal infiltration by large, spindle-shaped MCs with abnormal surface molecule expression (CD2 and CD25), a picture fully consistent with SM, according to the World Health Organization diagnostic criteria. A computed tomography scan showed diffuse lymphadenopathy, hepatosplenomegaly and diffuse small bowel involvement. Bone marrow aspirate and biopsy were diagnostic for SM; serum tryptase levels were increased (209 ng/mL, normal values < 20 ng/mL). The conclusive diagnosis was smouldering SM. There were no therapeutic indications except for treatment of symptoms. The patient was strictly followed up because of the risk of aggressive evolution.