Fracture risk in living kidney donors: a matched cohort study

Am J Kidney Dis. 2012 Jun;59(6):770-6. doi: 10.1053/j.ajkd.2012.01.013. Epub 2012 Apr 1.

Abstract

Background: Chronic kidney disease increases the risk of bone fragility fractures (osteoporotic fractures). Living kidney donors lose 50% of their renal mass and show changes in calcium homeostasis. We studied whether living kidney donation increases the risk of fragility fracture.

Design: Retrospective matched-cohort study.

Setting & participants: We reviewed the medical charts of all 2,015 adults in Ontario, Canada, who donated a kidney between 1992 and 2009 (surgeries performed across 5 transplant programs). We linked this information to health care databases and randomly selected 20,150 matched nondonors from the healthiest portion of the general population. Median age was 43 (95% CI, 24-50) years at study enrollment. Donors and nondonors were then followed up for a median of 6.6 years and a maximum of 17.7 years.

Predictor: Living donor nephrectomy.

Outcomes: The primary outcome was lower- and upper-extremity fragility fractures. Individuals who reached 66 years or older in follow-up had bisphosphonate prescriptions recorded.

Results: The rate of fragility fracture was no higher in donors compared with nondonors (16.4 vs 18.7 events/10,000 person-years; rate ratio, 0.88; 95% CI, 0.58-1.32). Results were similar in multiple additional analyses. There was little difference in the proportion of older adults in follow-up who received a bisphosphonate prescription (17.1% vs 15.2%; P = 0.4).

Limitations: These are interim results. Ongoing surveillance of this and other donor cohorts is warranted to be sure an association does not manifest with longer follow-up.

Conclusions: To date, there is no evidence of increased fragility fracture risk in living kidney donors. Our results meet an information need and are reassuring for the safety of the practice.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Age Distribution
  • Case-Control Studies
  • Confidence Intervals
  • Databases, Factual
  • Female
  • Follow-Up Studies
  • Fractures, Spontaneous / epidemiology*
  • Fractures, Spontaneous / etiology*
  • Fractures, Spontaneous / physiopathology
  • Humans
  • Incidence
  • Kidney Transplantation / methods*
  • Living Donors*
  • Logistic Models
  • Male
  • Middle Aged
  • Nephrectomy / adverse effects*
  • Nephrectomy / methods
  • Ontario / epidemiology
  • Poisson Distribution
  • Proportional Hazards Models
  • Reference Values
  • Retrospective Studies
  • Risk Assessment
  • Sex Distribution
  • Time Factors