Interobserver agreement in endoscopic evaluation of reflux esophagitis using a modified Los Angeles classification incorporating grades N and M: A validation study in a cohort of Japanese endoscopists

Abstract

The Los Angeles classification system is the most widely employed criteria associated with the greatest interobserver agreement among endoscopists. In Japan, the Los Angeles classification system has been modified (modified LA system) to include minimal changes as a distinct grade of reflux esophagitis, rather than as auxiliary findings. This adds a further grading M defined as minimal changes to the mucosa, such as erythema and/or whitish turbidity. The modified LA system has come to be used widely in Japan. However, there have been few reports to date that have evaluated the interobserver agreement in diagnosis when using the modified LA classification system incorporating these minimal changes as an additional grade. A total of 100 endoscopists from university hospitals and community hospitals, as well as private practices in the Osaka-Kobe area participated in the study. A total of 30 video clips of 30-40 seconds duration, mostly showing the esophagocardiac junction, were created and shown to 100 endoscopists using a video projector. The participating endoscopists completed a questionnaire regarding their clinical experience and rated the reflux esophagitis as shown in the video clips using the modified LA classification system. Agreement was assessed employing kappa (kappa) statistics for multiple raters. The kappa-value for all 91 endoscopists was 0.094, with a standard error of 0.002, indicating poor interobserver agreement. The endoscopists showed the best agreement on diagnosing grade A esophagitis (0.167), and the poorest agreement when diagnosing grade M esophagitis (0.033). The kappa-values for the diagnoses of grades N, M, and A esophagitis on identical video pairs were 0.275-0.315, with a standard error of 0.083-0.091, indicating fair intraobserver reproducibility among the endoscopists. The study results consistently indicate poor agreement regarding diagnoses as well as fair reproducibility of these diagnoses by endoscopists using the modified LA classification system, regardless of age, type of practice, past endoscopic experience, or current workload. However, grade M reflux esophagitis may not necessarily be irrelevant, as it may suggest an early form of reflux disease or an entirely new form of reflux esophagitis. Further research is required to elucidate the pathophysiological basis of minimal change esophagitis.

Epidemiology and clinical characteristics of GERD in the Japanese population

“…Grade M is defined as minimal changes to the esophageal mucosa, such as reddish erythema and/or whitish turbidity [12]. Although the definition of reflux esophagitis depends on the individual study, GERD defined as LA classification grade A or more, termed ''erosive esophagitis,'' could exclude interobserver bias because of the extremely poor agreement in the endoscopic diagnosis of grade M [14,15].…”

“…Because interobserver agreement on grade M is extremely poor, [14,15] and because the two large studies [29,30] combined cases of grade C and grade D, and because the LA classification for grade C and grade D was revised in 1999, [60] we analyzed the severity of erosive esophagitis as grade A, grade B, and grade C ? D. A total of 9782 cases with erosive esophagitis were analyzed.…”

Long-term outcomes of Roux-en-Y and Billroth-I reconstruction after laparoscopic distal gastrectomy

“…Endoscopic findings of the gastric remnant were evaluated according to the ''residue, gastritis, bile'' (RGB) classification system [18]. Signs and symptoms of gastroesophageal reflux disease were evaluated according to the modified Los Angeles classification system [19]. Body weight, serum albumin level, and serum total cholesterol level were measured as nutritional parameters, and the relative values (ratio of the postoperative value at 5 years to the preoperative value) were calculated.…”

Carcinogenesis of Barrett’s esophagus: a review of the clinical literature

“…Many investigators have pointed out that the endoscopic diagnosis of ultra-short BE is difficult and highly unreliable [12,[21][22][23]. The overall reliability coefficients for the endoscopic recognition of BE C1 cm was 0.72, whereas for the endoscopic recognition of BE \1 cm of columnarlined epithelium (CLE), the coefficient was only 0.22 [12].…”