Inter and Intraobserver Variation in Interpretation of Fecal Loading on Abdominal Radiographs

Abstract

Objectives: 

The current gold standard for the diagnosis of functional constipation is the ROME IV criteria. European Society for Pediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) and North American Society for Pediatric Gastroenterology, Hepatology & Nutrition (NASPGHAN) guidelines do not support the use of abdominal X-rays in establishing the diagnosis of constipation. Despite these recommendations, abdominal radiography is frequently performed to diagnose constipation. The objective of our study is to evaluate inter and intraobserver variation in interpretation of fecal loading on abdominal radiographs.

Methods: 

Electronic records of 100 children seen in the emergency room for gastrointestinal symptoms who had an abdominal radiograph performed were included. Four physicians from each specialty including gastroenterology, radiology, and emergency medicine interpreted the radiographs independently. Initially, subjective interpretations, followed by interpretations for intraobserver variation were obtained. Subsequently, all physicians were trained and asked to score the X-rays objectively using Barr and Blethyn scoring systems. Consistency between inter and intraobserver ratings of radiographic interpretation was evaluated using the Kappa coefficient (k) which ranges from 0 (no agreement) to 1.0 (perfect agreement).

Results: 

For subjective interpretations, k values showed a fixed margin k of 0.18 indicating poor agreement among 12 observers. Intraobserver k to look for reproducibility showed significant variability ranging from 0.08 (poor) to 0.61 (fair) agreement. Objective scoring results for Blethyn showed a k of 0.14 indicating poor agreement among 12 providers.

Conclusions: 

Reliability and reproducibility of X-rays for diagnosis and grading of constipation is questionable given poor to fair agreement for both inter and intraobserver comparisons. Our study supports the current recommendation of ESPGHAN and NASPGHAN to not use abdominal X-rays to diagnose constipation.