Risk evaluation of above-knee amputation and mortality according to ABO blood groups in patients with diabetic foot

Aims: This study aimed to assess the distribution of ABO blood groups in diabetic patients who underwent major joint amputation and to identify which blood group is related to the risk of above-knee amputation (AKA) and mortality. Methods: This retrospective study included 120 diabetic foot patients who underwent major lower-extremity amputation between January 2020 and January 2024. Demographic, clinical, and laboratory data were retrospectively collected from electronic patient records. Patients were stratified by ABO blood group, and the frequency of AKA and mortality rates were compared across groups. Results: The mean age of patients were 66.5 ± 11.9 years and median disease duration was 17 years. The frequency of AKA was 46.3% in blood group A, 54.2% in blood group B, 50% in blood group AB, and 28.2% in blood group O. AKA and mortality rates were higher in patients with non-O blood groups than in those with blood group O (28.2% vs. 49.4%, p = 0.032 for AKA; 48.7% vs. 67.9%, p = 0.048 for mortality; respectively). Independent of other confounders, blood group O had a 3.12-fold (1/OR) lower risk of AKA (OR =0.32, p = 0.049) and a 2.17-fold (1/HR) lower risk of mortality (HR =0.46, p = 0.045) compared to non-O blood groups. Conclusion: This study identifies ABO blood group as a potential factor influencing amputation severity and mortality in diabetic foot patients. Blood group O appears to confer a protective effect against AKA and mortality, whereas non-O groups, particularly B, show a tendency toward worse outcomes.