Direct medical costs in the preceding, event and subsequent years of a first severe hypoglycaemia episode requiring hospitalization: A population-based cohort study

Aims We aimed to estimate the use of healthcare services and the direct medical costs accrued by patients with diabetes mellitus (DM) during the year of the first severe hypoglycaemia (SH) event, as well as during the years before and after the event year. Materials and Methods We analysed a population-based, retrospective cohort including all adults with DM managed in the primary care setting from the Hong Kong Hospital Authority between 2006 and 2013. DM patients for whom SH was first recorded during the designated period were identified and matched to a control group of patients who had not experienced an SH event using the propensity score method. Direct medical costs in the years before, during and after the first SH event were determined by totalling the costs of health services utilized within respective years. Results After matching, a total of 22 694 DM patients were divided into the first recorded-SH group (n = 11 347) and the non-SH control group (n = 11 347). Patients for whom SH was first recorded, on average, made 7.85 outpatient clinic visits, made 1.89 emergency visits and spent 17.75 nights hospitalized during the event year. Mean direct medical costs during the event year were 11 751 US$, more than 2-fold that during the preceding year (4846 US$; P < 0.001) and subsequent years (4198-4700 US$; P < 0.001) and was 4.5 times that 2 years before the event (2481 US$; P < 0.001). Incremental costs of SH patients vs matched controls during the event year and the preceding year were 10 873 US$ (P < 0.001) and 3974 US$ (P < 0.001), respectively. Conclusions SH is associated with excessive hospital admission rates and direct medical costs during the event year and, in particular, during the year before as compared to patients who had not experienced an SH event.