Derivation of a clinical prediction rule for the noninvasive diagnosis of varices in children

Clinical prediction rules for children: a systematic review

CONTEXT

The degree to which clinical prediction rules (CPRs) for children meet published standards is unclear.

OBJECTIVE

To systematically review the quality, performance, and validation of published CPRs for children, compare them with adult CPRs, and suggest pediatric-specific changes to CPR methodology.

METHODS

Medline was searched from 1950 to 2011. Studies were selected if they included the development of a CPR involving children younger than 18 years. Two investigators assessed study quality, rule performance, and rule validation as methodologic standards.

RESULTS

Of 7298 titles and abstracts assessed, 137 eligible studies were identified. They describe the development of 101 CPRs addressing 36 pediatric conditions. Quality standards met in fewer than half of the studies were blind assessment of predictors (47%), reproducibility of predictors (18%), blind assessment of outcomes (42%), adequate follow-up of outcomes (36%), adequate power (43%), adequate reporting of results (49%), and 95% confidence intervals reported (36%). For rule performance, 48% had a sensitivity greater than 0.95, and 43% had a negative likelihood ratio less than 0.1. For rule validation, 76% had no validation, 17% had narrow validation, 8% had broad validation, and none had impact analysis performed. Compared with CPRs for adult health conditions, quality and rule validation seem to be lower.

CONCLUSIONS

Many CPRs have been derived for children, but few have been validated. Relative to adult CPRs, several quality indicators demonstrated weaknesses. Existing performance standards may prove elusive for CPRs that involve children. CPRs for children that are more assistive and less directive and include patients' values and preferences in decision-making may be helpful.

Non-invasive methods can predict oesophageal varices in patients with biliary atresia after a Kasai procedure

BACKGROUND

After a Kasai procedure, 70% of patients with biliary atresia develop chronic liver disease with portal hypertension and oesophageal varices.

AIMS

To investigate the role of new non-invasive parameters in predicting the presence of varices in patients with biliary atresia after a Kasai procedure and to identify the cut-off values of these parameters in predicting the presence of varices.

METHODS

31 patients with biliary atresia who had undergone a Kasai portoenterostomy were studied. Clinical, biochemical and abdominal ultrasound examination, liver stiffness measurement (LSM), LSM-spleen diameter to platelet ratio score (LSPS) and upper digestive endoscopy were performed.

RESULTS

15 (47%) patients had oesophageal varices (Group A) and 16 had no varices (Group B). Median values of LSM (kPa) and LSPS were significantly higher in Group A than in Group B (LSM: 17.0 vs. 7.5, respectively; p=0.0001; LSPS: 19.62 vs. 2.94, respectively; p=0.0001). The optimal cut-offs for predicting oesophageal varices were: LSM>10.6 kPa (sensitivity: 87%, specificity: 87.5%, PPV: 87%, NPV: 87.5%, and AUC: 0.92) and LSPS ≥9.2 (sensitivity: 91%, specificity: 92%, PPV: 91%, NPV: 92%, and AUC: 0.96).

CONCLUSIONS

Non-invasive methods can predict the presence of oesophageal varices in patients with biliary atresia; the sequential use of two non-invasive methods improves accuracy.

Variation in care for children with esophageal varices: a study of physicians', patients', and families' approaches and attitudes

BACKGROUND AND AIMS

Inadequate evidence to guide the management of children with esophageal varices may lead to variation in care and the provision of poor-quality care to some children. The aims of the study were to describe approaches taken by pediatric gastroenterologists for the management of esophageal varices in children, and to determine the attitudes of children, parents, and physicians toward screening endoscopy for identification of varices.

METHODS

Canadian pediatric gastroenterologists and hepatologists were questioned about their approaches to screening for esophageal varices and therapy to prevent or treat variceal hemorrhage. Consecutive children with portal hypertension and their parents were surveyed about attitudes to screening endoscopy.

RESULTS

Forty-seven of 72 (65%) physicians responded. Seventy percent of respondents screen for esophageal varices in selected children, most using endoscopy (77%). Fifty-eight percent of respondents who screen for varices would provide primary prophylactic treatment. Most would treat an acute variceal bleed with antibiotics, acid suppression, octreotide, and endoscopy within 24 hours (76%) and then secondary prophylaxis with endoscopic variceal ligation (96%) or β-blockers (28%). Among 29 families surveyed, 63% of parents and 50% of patients would agree to screening endoscopy to understand their risk of variceal bleeding and 67% if prophylactic therapy were available. Families were more concerned about the risk of endoscopic adverse events than were gastroenterologists.

CONCLUSIONS

Pediatric gastroenterologists vary in the care they provide for children at risk for esophageal varices and their attitudes toward the role of screening endoscopy differ from that of their patients. Further evidence is required to support practice guidelines that may reduce variation in care and thus improve its quality.

Can serum fibrosis markers predict medium/large oesophageal varices in patients with liver cirrhosis?

BACKGROUND AND STUDY AIMS

Non-invasive predictors of medium/large oesophageal varices (LOVs) could reduce the number of screening endoscopies. As portal hypertension is a consequence of liver fibrosis, serum fibrosis markers were evaluated together with other variables as possible non-invasive predictors of medium OV/LOV.

PATIENTS AND METHODS

A total of 154 cirrhotic patients with splenomegaly and 30 healthy control subjects were recruited in a prospective study in two gastroenterology centres in Upper Egypt. Clinical parameters assessed included Child-Pugh class, liver size and ascites. Laboratory parameters included complete blood count, liver function tests, and aspartate aminotransferase (AST)/platelet ratio. Transforming growth factor-β(1) (TGF-β(1)), alpha(2) macroglobulin (A(2)M) and hyaluronic acid (HA) were assayed. Ultrasonographic examination was done for assessment of liver span, portal vein diameter and detection of minimal ascites. Oesophageal varices were diagnosed and graded by oesophagogastroduodenoscopy.

RESULTS

Fifty-four patients (35%) had no or small varices and 100 (65%) patients had medium OV/LOV by endoscopy. On multivariate analysis, the independent predictors of medium OV/LOV were the presence of ascites (β=0.258, p=0.047) and serum HA (β=0.449, p=0.009). The receiver operating characteristic curve for HA showed the area under the curve to be 0.916. The sensitivity, specificity, positive and negative predictive values and diagnostic accuracy of HA at a cut-off value of 207μgl(-1) were 94%, 77.8%, 88.7%, 87.5% and 88.3%, respectively.

CONCLUSIONS

The presence of ascites and serum HA level higher than 207μgl(-1) can predict the presence of medium OV/LOV in cirrhotic patients. This would help physicians to identify patients who would most likely benefit from screening endoscopy and thus, reduce costs and discomfort from unnecessary endoscopic procedures.

Primary prophylaxis of variceal hemorrhage in children with portal hypertension: a framework for future research

Nonselective β-blocker therapy and endoscopic variceal ligation reduce the incidence of variceal hemorrhage in cirrhotic adults, but their use in children is controversial. There are no evidence-based recommendations for the prophylactic management of children at risk of variceal hemorrhage due to the lack of appropriate randomized controlled trials. In a recent gathering of experts at the American Association for the Study of Liver Diseases annual meeting, significant challenges were identified in attempting to design and implement a clinical trial of primary prophylaxis in children using either of these therapies. These challenges render such a trial unfeasible, primarily due to the large sample size required, inadequate knowledge of appropriate dosing of β-blockers, and difficulty in recruiting to a trial of endoscopic variceal ligation. Pediatric research should focus on addressing questions of natural history and diagnosis of varices, prediction of variceal bleeding, optimal approaches to β-blocker and ligation therapy, and alternative study designs to explore therapeutic efficacy in children.