OBJECTIVES: Severe (requiring another person’s assistance) hypoglycaemic events (SHEs) matter from clinical and economic perspective. Various risk factors are mentioned in the literature (drugs used, patients’ adherence, diet, exercise). We aimed to compare diabetes mellitus (DM) treatment patterns in Croatia, Czech Republic, Hungary, Poland and Slovenia with respect to the resulting risk of SHE. METHODS: We performed a systematic review to assess the drug related annual SHE rates for various treatments (shown in past ISPOR meetings) defined depending on using oral antidiabetic medications, sulfonylureas, insulins–split into basal-bolus/biphasic, and analogues/human. Epidemiological data were based on national registries, prescription databases, published studies, questionnaire surveys. Market shares were based on IMS data (Croatia, Czech Republic, Poland), National Health Insurance Fund (Hungary), prescription database (Slovenia). RESULTS: Using SHE rates estimates for individual treatment schemes and epidemiological and market data we arrived at the following estimates of the annual total number of SHEs: Croatia – 16,975, Czech Republic – 80,884, Hungary – 62,282, Poland – 217,711, and Slovenia – 9,291. When expressed per one DM patient we got annually: 0.078, 0.117, 0.143, 0.120, 0.096, respectively, which shows that usage of drugs associated with higher SHE risks varies between countries. E.g. in type 1 DM 42.65% patients in Hungary use basal-bolus with human basal (related to 1.1 events/person-year), while only 8% in Croatia. In type 2 DM 9.37% patients in Hungary use basal-bolus regimen with basal human insulin (0.6 events /person-year), and only 0.5% in Croatia. CONCLUSIONS: Rates of SHEs differ for T1, T2 and drug regimens. Various treatment schemes prevail in analysed countries, which result in different total (estimated) risks. However, other factors may impact the actual SHE incidence and motivate treatment selection in the first place. Therefore the results should not be used to draw conclusions regarding the overall quality of DM patients care.