ABO Blood Type and Clinical Characteristics Among Japanese Patients With Ulcerative Colitis

Background The ABO blood type has been associated with several digestive diseases. Some evidence has shown an association between ABO blood type and clinical outcomes among Asian patients with Crohn's disease. However, there are no reports about the association between ABO blood type and clinical outcomes in ulcerative colitis (UC). In this study, we aimed to evaluate the association between ABO blood type and clinical characteristics among patients with UC. Methodology The study subjects consisted of 277 Japanese patients with UC. Information on clinical characteristics and ABO blood type data was collected using medical records and a self-reported questionnaire. The information on clinical remission was collected using medical records. The definition of mucosal healing (MH) and partial MH was Mayo endoscopic subscore of 0 or 0-1, respectively. Results Of the enrolled patients, 39.4% (109/277), 18.4% (51/277), 29.2% (81/277), and 13.0% (36/277) had blood types A, B, O, and AB, respectively. The mean current age, age at onset of UC, and body mass index were 51.3 years, 42.1 years, and 22.7 kg/m², and the proportion of male patients was 59.2% (164/277). The proportion of patients with clinical remission, MH, partial MH, and prednisolone use were 58.1% (161/277), 25.6% (71/277), 63.2% (175/277), and 21.3% (59/277), respectively. Conclusions None of the blood types were associated with any of the variables in this study. Among Japanese patients with UC, ABO blood type might not be associated with clinical characteristics.