OBJECTIVEThis study aimed to compare the rate of hypoglycemic events from all spontaneously reported adverse events (AEs) between insulin detemir and insulin degludec using the Korea Adverse Event Reporting System (KAERS) database.MATERIALS AND METHODSWe analyzed data on the reported hypoglycemia events retrieved from adverse drug reactions (ADR) on the use of different insulin types from 2016 to 2017 in the Korea Institute of Drug Safety & Risk Management-Korea Adverse Event Reporting System Database (KIDS-KD). After defining hypoglycemic events as the AE of interest, we performed a disproportionality analysis by calculating the reporting odds ratio (ROR) to identify the disproportionality of AEs following treatment with insulin degludec (IDeg) and insulin detemir (IDet). Because spontaneously reported hypoglycemic events were not distinguished between insulin glargine 100 U/mL (Gla-100) and insulin glargine 300 U/mL (Gla-300) due to same ATC code by KIDS-KD, direct comparisons of Gla-100 and Gla-300 or comparisons of each analog of insulin glargine vs. IDet or IDeg, respectively, could not be achieved.RESULTSOf the 3,220 AEs caused by the use of long-acting basal insulin, 739 and 296 were caused by IDeg and IDet, respectively. Among these, 172 (23.3%) of the 739 and 83 (28.0%) of the 296 AEs were reported to be hypoglycemic events caused by IDeg and IDet, respectively. The rate of reported hypoglycemic events caused by IDeg was lower than that of IDet (ROR (95% CI): 0.78 (0.71 - 0.86)). Further, IDeg consistently caused lower hypoglycemia events than IDet in the sensitivity analysis (ROR (95% CI): 0.41 (0.37 - 0.46)).CONCLUSIONWhen we compared the proportionality of hypoglycemic events among the total number of reported AEs for each of the two basal insulins through disproportionality analysis using the spontaneous ADR reporting system, IDeg showed a relatively lower rate of reported hypoglycemic events than IDet.