Background and objectives: The impact of diabetes mellitus (DM) on the practice of peripheral nerve block anesthesia was mostly investigated in animal researches, and effects on human models are required to be clarified. The investigators performed this study to explore whether the presence of DM would affect the outcomes of axillary brachial plexus blocks (ABPBs) in patients undergoing elective forearm and/or hand surgery. The primary hypothesis was that the sensory block duration would be delayed in diabetic patients.