Background: currently, the level of HbA1c does not necessarily allow for the understanding of glycemic control. Considering this, glycemic variability (GV) is extensively studied in recent years. Psychological component has a significant impact on GV as the fear of hypoglycemia (FOH) and its consequences can reduce the motivation for achieving target glycemia and HbA1c as well as adherence to treatment.Aim: to assess GV in patients with type 1 diabetes with the elevated and target levels of HbA1c and to analyze the effect of FOH on diabetes control.Patients and Methods: 78 patients with type 1 diabetes who received insulin therapy (multiple daily injections or continuous subcutaneous insulin infusion) were enrolled. All patients were divided into two groups based on HbA1c levels, i.e., group 1 (patients who achieved individual HbA1c target level, n=13) and group 2 (patients who did not achieve individual HbA1c target level, n=65). HbA1c levels and GV were measured in all patients using iPRO™2 Professional CGM system (Medtronic, Ireland). In addition, FOH was evaluated using the Hypoglycemia Fear Survey II (HFS-II).Results: in group 1, time in-range was significantly higher (p=0.013) while daily GV was significantly lower (p=0.023) than in group 2. HbA1c levels, the rate of severe hypoglycemia, and diabetes duration were lower among the patients with lower levels of FOH.Conclusion: studying GV can provide better understanding of diabetes control in patients with any HbA1c level. Optimized treatment strategy using HFS-II can attenuate the effects of frequent hypoglycemia on GV and HbA1c levels and improve treatment efficacy.KEYWORDS: glycemic variability, glycated hemoglobin, diabetes, continuous glucose monitoring, hypoglycemia.FOR CITATION: Volkova A.R., Chernaya M.E., Mozgunova V.S. et al. Impact of glycemic variability and the fear of hypoglycemia on type 1 diabetes control. Russian Medical Inquiry. 2020;4(6):324–328. DOI: 10.32364/2587-6821-2020-4-6-324-328.