Endocrine Abstracts

Objective: Bone strength post heart transplant (HT) is affected by many factors including glucocorticoids, calcineurin inhibitors, hypogonadism, vitamin D deficiency, secondary hyperparathyroidism and cachexia. Trabecular bone score (TBS), novel texture index derived from lumbar spinal DXA improves fracture risk assessment in several different high-risk populations, whereas it remains largely understudied in HT recipients. We aimed to evaluate factors that affect TBS after HT.

Materials and methods: We conducted cross sectional cohort study including 87 HT patients (69 males and 18 females),of median age 59.3 years (IQR 53–66.5) that were stratified according to post-transplantation time into Group l (less than 1 year after HT;22 patients), Group 2(1 to 3 years post HT; 15 patients) Group 3 (3 to 5 years post HT; 31 patients) andGroup 4(more than 5 years post HT; 19 patients). We compared TBS and BMD among those groups. In addition, we assessed impact of methylprednisolone, bisphosphonate, male hypogonadism and presence of vertebral fractures on TBS.

Results: Compared with Group 1, patients in the 2nd and 3rd Group had lower TBS (1.35 (IQR 1.26–1.41) vs 1.30 (IQR 1.26–1.36) vs 1.25 (IQR 1.17–1.29) respectively; (pairwise comparison between Group 1 and 3 P = 0.020)), whereas in Group 4 TBS was higher than in Group 3 and comparable to Group 2 (1.31 (IQR 1.23–1.38). By contrast, BMD and T values did not differ among the 4 groups. Body mass index (BMI) was significantly higher in each group along observed time period (Group 1 (22.6 kg/m² (IQR 21.1–24.4)) vs Group 2 (24.7 kg/m² (IQR 24.2–28.0) vs Group 3 (28 kg/m² (IQR 25.5–30.4)) vs Group 4 (27.6 kg/m² (IQR26.2–30.0); <0.001 pairwise comparison: Group 3 vs Group 1 P <0.001 and Group 4 vs Group 1 P <0.001). Methylprednisolone, bisphosphonates, presence of male hypogonadism and vertebral fractures had no impact on TBS.

Conclusions: TBS in HT patients significantly differed among groups stratified by time after transplantation, independently of treatment with methylprednisolone, bisphosphonates or presence of male hypogonadism and vertebral fractures. By contrast, BMD was comparable among all Groups over time, being considered as less sensitive indicator of bone strength over post-transplantation time. Spontaneous reversal of declining trend in TBS observed more than 5 years after transplantation along with gradual significant improvement in BMI, imply cardiac cachexia and its reversal as one of the potential impacts on bone microstructure. The role of TBSin this population needs further investigation in longitudinal studies.