Supplementary Material for: Risk factors for fractures in renal transplantation: a population-based cohort study

Introduction: Kidney transplant recipients are at an increased risk of fractures, and targeted preventive strategies are needed. Therefore, in this retrospective cohort study, we investigated a large population-based cohort to identify the transplant recipient-specific risk factors for fractures in Taiwanese kidney transplant recipients. Methods: We conducted a retrospective cohort study using the National Health Insurance Research Database. Patients who underwent renal transplantation between 2003 and 2015 were identified and followed until December 31, 2015 to observe the development of fractures. Variables associated with the development of post-transplant fractures were identified by calculating hazard ratios in a Cox regression model. Results: 5309 renal transplant recipients were identified, of whom 553 (10.4%) were diagnosed with post-transplant fractures. Independent predictors of post-transplant fractures included an age at transplant ≥65 years (p<0.001), female sex (p<0.001), fractures within 3 years prior to transplantation (p<0.001), and diabetes mellitus (p<0.001). In addition, daily prednisolone dose >2.9-5.3 mg/day (p<0.001), >5.3-8.7 mg/day (p<0.001) and >8.7 mg/day (p<0.001) were also independent predictors of post-transplant fractures. Conversely, the use of peritoneal dialysis before renal transplantation (p=0.021), hypertension (p=0.005), and the use of tacrolimus (p<0.001), azathioprine (p=0.006), mycophenolate mofetil/mycophenolic acid (p=0.002), mTOR inhibitors (p=0.004) and calcium supplements (p=0.009) were inversely correlated with post-transplant fractures. Conclusion: We recommend minimizing daily glucocorticoids as early and as far as possible in conjunction with immunosuppressive regimens such as tacrolimus, azathioprine, mycophenolate mofetil/mycophenolic acid, mTOR inhibitors and calcium supplements, especially in older female recipients, and in recipients with diabetes and a history of prior fractures.