ESPE Abstracts

Background: Simultaneous pancreas kidney transplantation (SPKT) is a standard treatment option for young adults with type I diabetes (T1D) and concurrent renal failure. Despite the long-term immunosuppressive therapy the patients have better glycemic control, normalized renal function and an improved quality of life. Whether this is also reflected in the skeleton is not that clear yet.

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 by pQCT at the forearm within 2 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 the difference between study start and end was tested by two-sample t.test.

Results: There were 32 patients (9 females) with T1D manifested at 18.3±9.7 (mean±SD) years and aged 44.2±9.6 years at the time of transplantation. The lumbar spine (LS) bone mineral density (BMD) was decreased at the baseline (Z-score -1.2±1.3, P<0.001), with 8/32 (25%) patients having BMD Z-score ≤ -2.0, but normalized at study end (Z-score -0.2±1.2, P=0.39), with only 2/32 patients with Z-score ≤ -2.0 (P=0.003 vs. baseline). In contrast to LS BMD, trabecular volumetric BMD (vBMD) at the radius remained low over the study follow up (Z-scores -1.3±1.2 at baseline and -1.3±1.0 at study end, respectively, P<0.001 for both), with 9/32 (28%) and 8/32 (25%) participants, respectively, having the Z-score ≤ -2.0. Similarly, the muscle area at the forearm was significantly decreased at both time points (Z-scores -2.2±1.6 and -1.6±1.4, respectively, P<0.001 for both), with no improvement over the study period (P=0.074). Interestingly, glycated hemoglobin significantly improved after transplantation (67.8±13.8 at study start vs. 38.9±7.0 mmol/mol at study end, P<0.001).

Conclusions: This is the first study examining the development of volumetric, size independent, BMD in patients with T1D after SKPT. Despite the improvement in glycaemic control, the trabecular vBMD and muscle area at the forearm remained decreased even 3 years after SPKT, while LS aBMD increased. Areal BMD may falsely indicate fracture risk reduction. However, the relation of our findings of the BMD development to fracture risk in these patients remains to be elucidated.