胃食道交界處型態之內視鏡分類法 — 一致性研究

Abstract

研究背景：現行內視鏡診斷胃食道逆流症的標準主要根據黏膜裂(mucosal break)，但診斷結果難與症狀吻合，且不易偵測所有的胃酸逆流，因此我們希望以更優良的判讀標準提升傳統內視鏡的診斷能力。Haruma在2007年依經驗提出胃食道交界處型態在內視鏡下可分為五類，並認為其中某類可能較容易導致胃食道逆流症。在計畫以臨床試驗證實這個分類與胃食道逆流症的相關之前，必須先確立分類，並設計一致性研究來驗證其可靠性。本研究目的為根據Haruma的經驗定義一個胃食道交界處之內視鏡分類法，並去除其中可能不適當的類型而成為簡化的分類法，再從中挑選最可靠的分類法。 研究方法：先行定義一個「原始5類別胃食道交界處分類法」，再收集250張健康檢查胃鏡的胃食道交界處標準照片，供7位內視鏡醫師依該分類法逐一判讀。依結果計算類別盛行率、評量者內在一致性、及評量者間一致性。再利用類別合併的方式簡化分類法，針對所有簡化方式重新計算其一致性，並與合併前、或其他合併方式之一致性作比較，據以從中挑選一致性最好的分類法。 結果：評量者內在一致性為kappa統計值0.5為0.79。「原始胃食道交界處分類法」之評量者間一致性指標為平均原始一致性(average raw agreement) 63.4%，平均kappa統計值(mean kappa) 0.42，整體加權kappa統計值(overall weighted kappa) 0.42。與其他共25個各種類別合併而簡化的分類法相較，製作26個分類法的一致性排名。先去除12個臨床上不可行的簡化分類法，再依照排名挑選。最終選擇兩種簡化分類法，一為2類別而另一為4類別，其平均kappa統計值/整體加權kappa統計值分別為0.57/0.55及0.52/0.51。 結論：本研究依照評量者間一致性的客觀標準，配合臨床可行性的判斷，而製定了兩個可靠的胃食道交界處之內視鏡分類法，並將以此進行分類與胃食道逆流症相關性的研究。

Background: Current endoscopic diagnostic criteria for gastro-esophageal reflux disease (GERD) depends on identification of mucosal breaks. However, the diagnosis badly correlates with symptoms and acid reflux. Therefore a refined diagnostic criteria is desirable. Based on personal experience, Haruma et al. proposed that human gastro-esophageal junctional (GEJ) morphology under endoscopy typically varied into 5 categories, and that certain category might be associated with GERD. Prior to prove this association, we plan to define a novel classification of GEJ morphology based on Haruma’s experience. And through category-manipulation and reliability test, we aim to propose a best classification suitable for further studies. Method: We defined an original 5-category GEJ morphological classification. Two hundreds and fifty standardized endoscopic pictures on GEJ from subjects underwent health check were collected, and subjected to ratings by 7 endoscopists. Categorical prevalence, intra-rater agreement, and inter-rater agreement were calculated. By post-hoc category combination procedures, we repeated the calculations for all 25 possible modified classifications, and compared the result to the original one and each other. The comparison formed the basis for selection. Result: Intra-rater agreements were kappa between 0.5 and 0.79. Inter-rater agreement of the original classification was presented by average raw agreement of 63.4%, mean kappa of 0.42, and overall weighted kappa of 0.42. Added by 25 modified classifications, a ranking of agreements was made for the total 26. Twelve of them were discarded because they were, by definition, not clinically applicable. Finally 2 classifications were selected, 2-category and the other 4-category. The mean kappa/overall weighted kappa was 0.57/0.55, 0.52/0.51, respectively. Conclusion: Based on inter-rater agreement and clinical applicability, our study has defined two reliable endoscopic classifications on GEJ. Both classifications are candidates for further association study with GERD.