Table 1: The OLGA staging system. Stage is scored in following way: 1) Scoring atrophy at each single antral/angular biopsy level (row) and corpus biopsy level (column); 2) Calculating mean of degree of atrophy in antral/angular level (A) and corpus level (C); 3) The final prevalence of atrophy at each compartment is calculated and scored on a four-tiered scale (no atrophy = 0%: score = 0, mild atrophy = 1-30%: score = 1, moderate atrophy = 31-60%: score = 2, severe atrophy => 60%: score = 3) .
|A0||Stage 0||Stage I||Stage II||Stage III|
|A1||Stage I||Stage I||Stage II||Stage III|
|A2||Stage II||Stage II||Stage II||Stage IV|
|A3||Stage III||Stage III||Stage IV||Stage IV|