Bone Benefits After Simultaneous Pancreas-kidney Transplantation Compared With the Pretransplant Period

Bone health is frequently compromised in patients with type 1 diabetes and advanced diabetic kidney disease. While simultaneous pancreas-kidney transplantation (SPKT) is the treatment of choice for selected patients, concerns remain about its skeletal impact, particularly because of immunosuppressive regimens.

We conducted a retrospective intraindividual comparison of bone mineral density (BMD) and trabecular bone score (TBS) before and after SPKT in 48 patients (mean age 41.5 ± 10.1 y) managed under a corticosteroid-sparing immunosuppressive protocol (tacrolimus + mycophenolate mofetil/sirolimus + prednisone only 4 wk after SPKT). Dual-energy X-ray absorptiometry scans were assessed at 3 time points: before listing, peritransplant (within 28 d from the date of SPKT, both before and after), and 2 y posttransplant. Annualized changes in BMD and TBS were analyzed along with predictors of bone outcomes.

During the pretransplant period, BMD declined significantly at the femoral neck (-0.011 g/cm 2 /year; 95% confidence interval [CI],-0.019 to -0.003) and TBS decreased by -0.032/year (95% CI, -0.049 to -0.014). After SPKT, lumbar spine BMD increased (+0.039 g/cm 2 /year; 95% CI, 0.028-0.050), TBS improved (+0.019/year; 95% CI, -0.000 to 0.039), and femoral neck BMD stabilized. Distal radius BMD declined posttransplant (-0.011 g/cm 2 /year; 95% CI, -0.018 to -0.004). Trend differences between pretransplant and posttransplant periods were significant for lumbar spine BMD ( P  < 0.001), femoral neck BMD ( P  = 0.01), and TBS ( P  = 0.003).

SPKT under a corticosteroid-sparing regimen not only halts but may reverse bone loss at trabecular rich sites in type 1 diabetes with advanced diabetic kidney disease. In particular, the increase in BMD in the lumbar spine can be considered clinically significant. Our data support the strategy of early referral for SPKT in eligible patients.