Introduction: Only a few large-scale studies have examined the care gap in Japan. The aim of this study was to investigate the persistence of and adherence to osteoporosis pharmacotherapy in Japan.
Materials and methods: The rates of continuation (persistence) of and adherence to osteoporosis pharmacotherapy were investigated using medical insurance data, issued from July 2013 to December 2018, from the medical care system for elderly individuals in Hokkaido, Japan.
Results: The study included 7918 male and 52,585 female patients. Persistence rates were 62.1% in the first year and 45.3% in the second year. There were 33,096 patients who discontinued medication; 8296 patients resumed medication during the observation period of 730 days. The median time to the discontinuation of medication for all the patients was 702 days. The 2-year medication possession ratio (MPR) was 63.8%; 30,989 patients (51.2%) had an MPR ≥ 80% and 20,788 (34.4%) had an MPR < 50%. Both the persistence and adherence were better in females than in males and worsened with increasing age. Comparisons of fracture history showed that persistence and MPR were higher in the no hip or vertebral fracture group, followed by hip fracture, vertebral fracture, and hip and vertebral fracture groups. Meanwhile, more patients in the hip fracture group had an MPR ≥ 80%.
Conclusion: Persistence of and adherence to osteoporotic pharmacotherapy are not very high in Japan. To bridge the care gap following osteoporosis pharmacotherapy, improvements are required for males, the elderly, and those with a history of vertebral fracture.
Keywords: Adherence; Care gap; Osteoporosis; Persistence; Pharmacotherapy.