MO961: Mineral Metabolism Parameters and Bone Density During The First Year of Kidney Transplantation
Authors: Maria Alfieri Carlo , Molinari Paolo , Teresa Gandolfo Maria , Regalia Anna , Rosaria Campise Maria , Cresseri Donata , Favi Evaldo , Castellano Giuseppe 
Published: May 2022

BACKGROUND AND AIMS

We evaluated retrospectively in a cohort of kidney-transplanted patients (KTxp), the variations of mineral metabolism (MM) parameters, femoral and vertebral bone density during the first year of kidney transplantation (KTx).

METHOD

383 KTxp (M = 232), up to the 650 transplanted in our Department (2004–2017) were studied. At 1st(T1) and 12th(T2) mth of KTx biochemical, femoral and vertebral dual-energy X-ray absorption (DEXA) data were recorded. T-score (Ts) -1 &gt;Ts &gt; -2.5 was considered Osteopenia (F-OPN/V-OPN) and Ts &lt; -2.5 osteoporosis (F-OPS/V-OPS).

RESULTS

The KTxp age and dialysis vintage (DV) were 48 ± 12 years and 53 ± 25 months; 67% of KTxp had a history of hemodialysis. In 82.5% of cases, a donor deceased KTx (DD) was performed and in 40% of KTxp had a previous history of steroid therapy. During the first year of KTx 91% and 93% of KTxp received respectively calcineurin inhibitors and mycophenolate, and the steroids cumulative dose (SCD) was 2683 ± 926 mg. At T1, cholecalciferol and calcifediol were supplemented in 5% and 8% of KTxp, and AT T12 in 12% and 15% of KTxp. An increase in BMI (23 ± 3 versus 24 ± 3 kg/m2 P &lt; 0.0001), Ca (9.82 ± 0.83 versus 9.9 ± 0.73 mg/dL, P &lt; 0.0001), P (2.4 ± 0.96 versus 3.1 ± 0.61 mg/dL, P  &lt; 0.0001), 25OH-D (14.4 ± 6.81 versus 18.8 ± 9.7 ng/mL, P  &lt; 0.0001), Hb (11.0 ± 1.4 versus 12.8 ± 1.5 g/dL, P  &lt; 0.0001), albumin (4.2 ± 0.38 versus 4.46 ± 0.35 g/dL, P  &lt; 0.0001) was observed. Serum creatinine (1.41 ± 0.4 versus 1.37 ± 0.3 mg/dL, P = 0.03), PTH (87 ± 73 versus 79 ± 86 pg/mL, P = 0.06 and ALP (107 ± 92 versus 93 ± 58 U/L, P  &lt; 0.0001) had a reduction.

Femoral bone mineral density (F-BMD) at T1 and F-Ts-T1 were 0.749 ± 0.17 g/cm2 and -1.55 ± 1.06. F-OPS-T1 was present in 17.5% and F-OPN-T1 in 53% of KTxp. F-BMD-T1 correlated directly with BMI-T1 (P  &lt; 0.0001) and inversely with 25OH-D-T1 (P  &lt; 0.004). F-Ts-T1 was inversely correlated with DV (P = 0.04), BMI-T1 (P &lt;0.0001) and PTH-T1 (P = 0.02). KTxp with F-OPS-T1 had longer DV and lower BMI (P = 0.02). At T12, F-BMD-T12 and F-Ts-T12 were 0.77 ± 0.67 g/cm2 (P = 0.17 versus F-BMD-T1) and −1.4 ± 0.9 (P = 0.002 versus F-Ts-T1).F-OPS-T12 was present in 13.2% of patients and F-OPN-T1 in 55.2%. F-BMD-T12 correlated directly with BMI-T12 (P  &lt; 0.04). F-Ts-T12 correlated inversely with DV (P = 0.004), Ca at T1 (P = 0.001) and T12 (P = 0.0005) and with [SCD at T12 (P = 0.02)]. Patients with F-OPS-T1 had longer DV (P = 0.004) and higher PTH at T1 and T12 (P = 0.04 and P = 0.08). F-DEXA category worsened in 3.5% of KTxp.

At T1, V-BMD-T1 and V-Ts-T1 were 0.92 ± 0.19 g/cm2 and −1.5 ± 1.58. V-OPS-T1 was present in 30% of KTxp and V-OPN-T1 in 34.5%. V-BMD-T1 correlated directly with BMI-T1 (P  &lt; 0.0001) and Ca-T1 (P = 0.04). V-Ts-T1 was inversely correlated with DV (P = 0.04), PTH-T1 (P = 0.02), Ca-T1 (P = 0.03), ALP-T1 (P = 0.01). A direct correlation between V-Ts-T1 and BMI-T1 (P  &lt; 0.0001) and 25OHD-T1 (P = 0.02) was present. V-OPS-T1 was more prevalent in males (P = 0.01).They had lower BMI (P  &lt; 0.0001), albumin (P = 0.02) and higher Ca-T1 (P = 0.008) and ALP-T1 (P = 0.03). 

At T12, V-BMD-T12 and V-Ts-T12 were 0.90 ± 0.22 g/cm2 and −1.5 ± 1 .33 (both NS versus T1). V-OPS-T12 was present in 27.7% of KTxp and V-OPN-T12 in 37.2%. V-BMD-T12 correlated directly with BMI-T1 and T12 (P  &lt; 0.0001 and P = 0.005) and inversely with Ca-T12 (P = 0.03) and SCD-T12 (P = 0.04). V-Ts-T12 was inversely correlated with DV (P = 0.004), SCD-T12 (P = 0.02) and with Ca at T1 (P = 0.001) and T12 (P = 0.0005). A direct correlation was found with BMI-T1 and T12 (P = 0.0002 and P = 0.001). V-OPS-T12 was more prevalent in DD (P = 0.001). They were older (P = 0.01), had longer DV (P = 0.01). BMI-T1 and T12 were lower in V-OPS-T12 (P = 0.002 and P = 0.03) and Ca-T12 higher (P = 0.01). SCD-T12 was higher in V-OPN-T12 and V-OPS-T12 (P = 0.05). V-DEXA category worsened in 32% of KTxp.

CONCLUSION

In the first year of KTx several modifications of MM are present. Both femoral and vertebral DEXA seem to be strongly related to the pre-KTx status, in particular, nutritional status and dialysis vintage are related to bone status at T1. Strong importance on T12 evaluation is taken by the SCD.