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Kidney Week

Abstract: TH-PO907

Vertebral Fracture Risk Is Increased Among Living Kidney Donors 25 Years After Donation: Survey-Based Study

Session Information

Category: Transplantation

  • 2102 Transplantation: Clinical

Authors

  • Maradit Kremers, Hilal, Mayo Clinic Minnesota, Rochester, Minnesota, United States
  • Grossardt, Brandon R., Mayo Clinic Minnesota, Rochester, Minnesota, United States
  • Kasiske, Bertram L., Hennepin Healthcare System Inc, Minneapolis, Minnesota, United States
  • Matas, Arthur J., Regents of the University of Minnesota, Minneapolis, Minnesota, United States
  • Khosla, Sundeep, Mayo Clinic Minnesota, Rochester, Minnesota, United States
  • Kremers, Walter K., Mayo Clinic Minnesota, Rochester, Minnesota, United States
  • Amer, Hatem, Mayo Clinic Minnesota, Rochester, Minnesota, United States
  • Kumar, Rajiv, Mayo Clinic Minnesota, Rochester, Minnesota, United States
Background

Living kidney donors may have an increased risk of fractures due to reductions in renal mass, lower concentration of 1,25-dihydroxyvitamin D, secondary increases in parathyroid hormone and bone turnover markers. We compared the long-term risk of fractures among living kidney donors with matched controls from the general population.

Methods

Surviving kidney donors from 3 transplant centers completed a survey about bone health and history of fractures. Age, sex, and race-matched non-donor controls without a history of comorbidities that would have precluded kidney donation were identified from population-based resources and completed the survey. The proportion of persons reporting fractures was compared using standardized incidence ratios (SIR).

Results

A total of 1,930 donors and 1,615 controls responded to the survey. Average time between donation/index date and survey date was 24.8 years for donors and 27.3 years for controls. At the time of the survey, donors were 1.1 years younger than the controls (67.4 vs 68.5 years). Although the overall rate of fractures in donors was significantly less than in controls (SIR 0.91; 95% CI 0.82-0.99), there were significantly more vertebral fractures in donors than in controls (SIR 1.43; 95% CI 1.06-1.86) and more hip fractures in women donors compared to controls (SIR 1.90; 95% CI 1.01-3.26).

Conclusion

Our findings suggest excess vertebral fractures in both men and women and excess hip fractures in women among living kidney donors compared to controls after 25 years of follow-up.

Age-, sex-, and time after index-standardized incidence ratios (SIRs) for fracture risk in donors vs. controls
 OverallWomenMen
Fracture siteObs.*Exp.†SIR (95% CI)‡Obs.*Exp.†SIR (95% CI)‡Obs.*Exp.†SIR (95% CI)‡
Any fracture reported420462.20.91 (0.82 to 0.99)282295.00.96 (0.85 to 1.07)138167.20.83 (0.69 to 0.98)
Fragility fracture153140.31.09 (0.92 to 1.28)10593.91.12 (0.92 to 1.35)4846.41.03 (0.76 to 1.37)
Hip2114.71.43 (0.89 to 2.19)136.81.90 (1.01 to 3.26)87.91.02 (0.44 to 2.01)
Lower arm or wrist9199.70.91 (0.74 to 1.12)6870.90.96 (0.75 tp 1.22)2328.80.80 (0.51 to 1.20)
Spine or back (vertebrae)5035.01.43 (1.06 to 1.88)3021.21.41 (0.95 to 2.02)2013.81.45 (0.89 to 2.24)

*Observed fractures in kidney donors. †Expected # of fractures in kidney donors by applying age-, sex-, and time after index-specific fracture rates observed in controls. ‡Standardized incidence ratio (SIR) for risk of fractures in kidney donors compared to risk in controls. SIR > 1.0 means more fractures in kidney donors than in controls.

Funding

  • NIDDK Support