Fracture risk and healthcare resource utilization and costs among osteoporosis patients with type 2 diabetes mellitus and without diabetes mellitus in Japan: retrospective analysis of a hospital claims database

Abstract

Background: Osteoporosis, osteoporosis-related fractures, and diabetes are considerable health burdens in Japan. Diabetes in patients with osteoporosis has been reported to be associated with increased fracture risk. This retrospective analysis of a Japanese hospital claims database investigated the real-world effect of type 2 diabetes mellitus (T2DM) on the incidence of clinical fractures, costs, and healthcare resource utilization in patients with osteoporosis and a subgroup of patients prescribed raloxifene.

Methods: Women aged ≥50 years diagnosed with osteoporosis who had a first prescription claim for osteoporosis treatment with a pre-index period ≥12 months and a post-index period of 30 months were selected from a database extract (April 2008-July 2013). Patients prescribed raloxifene were classed as a subgroup. Patients diagnosed with T2DM constituted the T2DM group; all other patients (excluding patients with type 1 diabetes mellitus) constituted the non-diabetes mellitus (non-DM) group. Groups were matched by exact matching, using selected baseline characteristics. Patient demographic and clinical characteristics were compared using chi-squared tests, t-tests, or Wilcoxon rank sum tests. Time to first fracture was examined using Kaplan-Meier survival analysis.

Results: Overall, the T2DM and non-DM groups had 7580 and 7979 patients, respectively; following matching, there were 3273 patients per group. In the raloxifene subgroup, the T2DM and non-DM groups had 668 and 699 patients, respectively; following matching, there were 239 patients per group. At baseline, the T2DM group (overall and raloxifene subgroup) had significantly higher healthcare resource utilization and comorbidities. During the post-index period, a similar pattern was observed in the overall group, even after matching; the T2DM group also had a higher incidence of fracture. In the raloxifene subgroup, after matching, there were no significant differences in fracture incidence or costs and fewer differences in healthcare resource utilization between the T2DM and non-DM groups.

Conclusions: These findings suggest that comorbid T2DM increases fracture incidence in patients with osteoporosis, compared with patients without DM. Increases in fracture incidence were accompanied by greater costs and healthcare resource utilization, which are important considerations for clinical practice in Japan. Further research investigating the use of raloxifene for treatment of osteoporosis with comorbid T2DM may also be warranted.

Keywords: Aged; Costs; Fracture; Healthcare resource utilization; Hospital claims database analysis; Japan; Osteoporosis; Raloxifene hydrochloride; Retrospective cohort study; Type 2 diabetes mellitus.

Fig. 1

Kaplan-Meier curve of time to first incident fracture for the overall study group, post-matching. Abbreviations: DM = diabetes mellitus; T2DM = type 2 diabetes mellitus

Fig. 2

Kaplan-Meier curve of time to first incident fracture for the raloxifene subgroup, post-matching. Abbreviation: DM = diabetes mellitus; T2DM = type 2 diabetes mellitus