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Abstract: FR-PO812

Clinical Significance of Incident Osteoporotic Fractures After Kidney Transplantation: A Nationwide Matched Comparative Cohort Study

Session Information

Category: Transplantation

  • 2002 Transplantation: Clinical

Authors

  • Jang, Yunyoung, Seoul National University Hospital, Jongno-gu, Seoul, Korea (the Republic of)
  • Kim, Ji Eun, Korea University Guro Hospital, Seoul, Korea (the Republic of)
  • Park, Jina, Biomedical Research Institute of Seoul National University Hospital, Seoul, Korea (the Republic of)
  • Park, Sehoon, Seoul National University College of Medicine, Seoul, Korea (the Republic of)
  • Kim, Yong Chul, Seoul National University Hospital, Jongno-gu, Seoul, Korea (the Republic of)
  • Joo, Kwon Wook, Seoul National University Hospital, Jongno-gu, Seoul, Korea (the Republic of)
  • Lee, Hajeong, Seoul National University Hospital, Jongno-gu, Seoul, Korea (the Republic of)
Background

Osteoporotic fracture is one of the main concerns of kidney transplantation recipients (KTR) due to mineral bone disorders and the use of immunosuppressive agents including glucocorticoid, although its incidence and clinical significance remains unclear.

Methods

We constructed a nationwide cohort consisting of 141,674 end-stage kidney disease patients from 2008 to 2020 using the National Health Insurance System database of Korea. We excluded patients experiencing parathyroidectomy and previous osteoporotic fracture or taking osteoporosis-treating medication. Then, we compared osteoporotic fracture incidence between KTRs and 1:1-matched dialysis patients. Osteoporotic fractures are defined as fractures associated with low bone mineral density including hip, spine, forearm, and humerus. After the comparison, we explored the effect of incident osteoporotic fracture after kidney transplantation on death and death-censored graft failure using fracture status as a time-varying covariate in an extended Cox model.

Results

After exclusion, 53964 dialysis patients and 12297 KTRs were included and their new-onset osteoporotic fracture was 8.0% of dialysis patients and 5.0% of KTRs, respectively. After matching, both groups showed similar incidence of osteoporotic fracture with 5.2% of dialysis patients and 5.6% of KTRs, respectively. During overall 5.7 ± 3.0 years of follow up, KTRs showed a lower risk for the incident osteoporotic fracture than matched dialysis controls (adjusted hazard ratio [aHR] 0.83, 95% CI 0.73-0.94, p = 0.04). Among osteoporotic fracture sites, the hip was significantly lower (aHR 0.43, 95% CI 0.33-0.57, p <0.001) in KTRs, although the other sites were not. Among KTRs, the incident osteoporotic fracture was associated with an elevated risk of mortality (aHR 2.07, 95% CI: 1.54-2.78, p<0.001), but not with death censored graft failure (aHR 1.29, 95% CI: 0.96-1.72, p= 0.087)

Conclusion

Incident osteoporotic fracture risk was significantly lower in KTRs than in patients remaining in dialysis. However, once it occurred in KTRs, it was associated with a higher mortality risk than in KTRs without experience of it.