Hill Grade Classification for Gastroesophageal Flap Valve
The Hill grade classification is a standardized endoscopic grading system used to assess the gastroesophageal flap valve (GEFV) competence, with grades III and IV indicating an abnormal valve that predicts gastroesophageal reflux disease with high specificity (73-76%), and should be routinely documented during upper endoscopy. 1, 2
Clinical Significance and Application
The Hill grade classification system evaluates the morphology and competence of the gastroesophageal junction during retroflexed endoscopic examination 1. This classification divides findings into:
- Grade I/II: Normal gastroesophageal flap valve 2
- Grade III/IV: Abnormal gastroesophageal flap valve 2
Patients with abnormal GEFV (grades III/IV) have nearly double the risk of symptomatic GERD compared to those with normal GEFV (risk ratio 1.88,95% CI 1.57-2.24). 2
Among patients already experiencing GERD symptoms, those with abnormal GEFV have more than twice the risk of developing erosive esophagitis compared to patients with normal GEFV (risk ratio 2.17,95% CI 1.40-3.36) 2.
Documentation Requirements
The American Gastroenterological Association recommends that standard terminology and classification systems, including Hill grade classification for the gastroesophageal flap valve, should be used when documenting endoscopic findings 1.
At minimum, photodocumentation should include at least one representative photograph of the gastroesophageal junction/fundus in retroflexed view, which is where Hill grade assessment is performed. 1
Diagnostic Performance
The specificity of abnormal GEFV for predicting symptomatic GERD is 73.3% (95% CI 69.3-77.0%) 2. For erosive esophagitis in patients with symptomatic GERD, the specificity increases to 75.7% (95% CI 65.9-83.4%) 2.
This high specificity means that when you identify an abnormal flap valve (grades III/IV), you can be confident that gastroesophageal reflux pathology is present, making it a valuable clinical tool for risk stratification 2.
Clinical Pitfalls
Do not confuse Hill grade classification (for gastroesophageal flap valve assessment) with variceal grading systems. Hill grade has no role in assessing esophageal varices, which require separate documentation of variceal size (<5 mm vs >5 mm) and red color signs 3, 4.
The Hill classification provides reproducible endoscopic grading but is underutilized in routine clinical practice despite its demonstrated accuracy and consistency 2. Incorporating this assessment into standard upper endoscopy reports enhances diagnostic yield for GERD evaluation 2.