Background: Following kidney transplantation (KTx), episodes of hyperkalemia are common and effectively treated with sodium zirconium cyclosilicate (SZC, Lokelma) or patiromer (PAT, Veltassa). The presence of SZC/PAT in the gastrointestinal tract may, if radio dense, influence the interpretation of lumbar spine (LS) dual-energy x-ray absorptiometry (DXA)-scans. We investigated the effect with/without PAT/SZC in KTx on LS DXA readings.
Methods: A prospective, single-center study of KTx recipients in need of potassium-lowering therapy was performed. All participants performed two LS DXA-scans, the first after at least 3 days of SZC/PAT treatment and the second after a 2-week washout.
Results: Eighteen KTx patients (8 SZC, 10 g/day vs. 10 PAT, 8.4 g/day) were included and provided two valid DXA-scans (mean age 63 ± 12 years, 12 males). The change in LS BMD determinations in the SZC group was 2.48 ±12.21%, while there was no change in the PAT group, -0.25 ± 2.28%. The absolute root mean squared difference (RMSD) change was 0.102 ± 0.084 g/cm2 and 0.021 ±0.013 g/cm2 after SZC and PAT washout, respectively (p = 0.008).
Conclusion: In KTx, treatment with SZC, but not PAT, significantly influenced the DXA-scan interpretation of the LS region. After a 2-week washout period, SZC interference was without clinical implications on DXA-scans.
Summary: The potassium lowering drug sodium zirconium cyclosilicate (Lokelma) is radiopaque and therefore acts as a confounder on DXA interpretations in kidney transplant recipients. Patiromer (PAT, Veltassa) has no such effect.
Keywords: BMD; DXA; patiromer; potassium‐binder therapy; sodium zirconium cyclosilicate.
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