Geographical variation in the use of glucose-lowering drugs in type-2 diabetes in Denmark: A nationwide drug utilization study

AIMS: To analyse geographical variation in use of glucose-lowering drugs (GLDs) for type-2 diabetes (T2DM) in Denmark.

METHODS: We included all adults who filled a prescription for a non-insulin GLD indicated for T2DM from 2010 to 2023 in Denmark. Stratified by each of the five regions, we calculated the annual incidence rate, the annual prevalence proportion and the total volume of dispensed GLDs from 2010 to 2023. We calculated the proportion of incident prescriptions for GLDs that were issued by different prescriber types and characterized non-insulin GLD users in each region in 2023. Finally, we analysed variation at the municipal level.

RESULTS: Totally, data from 478 118 adults were included. The user characteristics were comparable across the regions with no differences in the median age (range 66-67 years) or in the sex distribution (range 56-58% males). In all regions, general practitioners were the main prescribers of GLDs. There were minor regional differences in the use of GLDs, with a predominant and increasing use of metformin, accelerating use of SGLT-2is and GLP-1RAs, and declining use of SUs over time. In Q4 2023 the ranges of prevalence per 1000 inhabitants were 31 to 44 for metformin, 16 to 23 for SGLT2is, 14 to 23 for GLP-1RAs and 1.37 to 1.58 for SUs. There were some differences in characteristics of GLD users across regions, with a slightly higher prevalence of diabetes-related complications and larger involvement of hospital physicians in the Capital Region compared to the other regions. We identified four municipality clusters that differed marginally in the prescribing pattern of non-insulin GLD.

CONCLUSION: The minor differences in the use of GLDs indicate equal access to GLDs across Denmark. Differences at the municipal level call for future studies to investigate if these reflect differences in clinical practice or differences in T2DM populations.