Bone Abstracts

Objectives: Simultaneous pancreas kidney transplantation (SPKT) is a standard treatment option for adults with long-lasting (usually adolescence onset) type 1 diabetes (T1D) and concurrent renal failure. Despite the need for life-long immunosuppressive therapy the patients achieve better glycemic control, normalized renal function and an improved quality of life. Whether metabolic improvement is also reflected in the skeleton is not yet clear.

Methods: Patients were prospectively followed after SPKT performed at a single tertiary center between November 2011 and December 2014. Besides routine blood tests, the subjects were scanned by DXA at the spine and femur and by pQCT at the forearm within 3 months and then 1.3 and 3.3 years after the transplantation. One sample t-test was used to analyze the difference of the Z-scores of the bone parameters from zero and study end was compared to baseline by the two sample t-test.

Results: There were 32 patients (9 females) with T1D aged 44.2±9.6 years (mean±S.D.) at the time of transplantation, mean age at T1D manifestation was 17.7±9.6 years. The lumbar spine (LS) bone mineral density (BMD) was decreased at the baseline (Z-score −1.2±1.3, P<0.001), 8/32 (25%) patients had BMD Z-score ≤ −2.0. The mean LS BMD Z-score normalized at the study end (Z-score −0.2±1.2, P=0.39). The femoral neck (FN) BMD was low at the baseline (Z-score −1.5±0.9, P<0.001), 10/32 (31%) patients had BMD Z-score ≤ −2.0. The FN BMD Z-score was still low at the study end (Z-score −1.2±0.9, P<0.001) and did not change significantly 3 years post transplantation (P=0.31). In contrast to LS BMD, trabecular volumetric BMD (vBMD) at the metaphysis of the radius was low at both time points (Z-scores −1.3±1.2, resp. −1.3±1.0; P<0.001 for both). Cortical vBMD assessed at the diaphysis of the radius was normal at baseline and also at study end (Z-scores 0.0±1.3, P=0.98; and −0.45±1.5, P=0.09, respectively). Similar findings were observed for the Strength-Strain Index.

Conclusion: This is the first study examining the development of volumetric, size independent, BMD in patients after SPKT. How do the discordant areal and volumetric BMD findings relate to fracture risk in these patients remains to be elucidated.

Disclosure: The authors declared no competing interests.