Understanding regional patterns of pharmaceutical use is essential for effective resource allocation and promoting rational drug use. The NDB Open Data of the Ministry of Health, Labor and Welfare offers a high-quality national database that comprehensively captures usage patterns. However, direct comparisons based on prescription volume are challenging owing to differences in drug formulations and dosages, and increasing generic drug use. This study examined sodium–glucose transport protein 2 inhibitor (SGLT2i) usage patterns across Japanese prefectures by comparing prescription quantities and drug costs using the NDB Open Data. Using the NDB Open Data, we extracted single-component SGLT2i formulations (pharmacological classification 396) and calculated the Defined Daily Dose (DDD) per 1000 inhabitants per day (DID) using WHO Anatomical Therapeutic Chemical (ATC) codes. During the fiscal year 2022, urban prefectures, including Tokyo, Kanagawa, Osaka, Aichi, and Saitama, recorded the highest SGLT2i prescription quantities. Conversely, DID values were notably higher in rural areas such as Fukushima, Tochigi, Kagawa, Oita, and Iwate, indicating notable regional differences that could not be explained solely by population size. Annual prescriptions consistently increased across all drugs, reflecting the impact of expanded indications and product discontinuation. Canagliflozin demonstrated relatively low domestic usage in DID despite a similar number of tablets prescribed compared to other drugs, suggesting distinct regional prescription patterns. Combining the NDB Open Data with the ATC/DDD system identified regional SGLT2i usage. This approach could enable standardized comparisons within drug classes, providing invaluable evidence to support appropriate drug use guidelines and informed policy formulations.
Miyake et al. (Wed,) studied this question.