Prevalence and patterns of bone loss in the first year after renal transplant in South East Asian patients

Abstract

Background: Limited data are available regarding patterns of bone loss in South East Asian renal transplant patients. We aimed to determine the prevalence of low bone density and factors contributing to bone loss in Singaporean patients in the first year after renal transplant.

Methods: Seventy-nine consecutive patients who underwent renal transplant were evaluated. Bone mineral density (BMD) was evaluated at 0 (baseline), and at 6 and 12 months after transplant. Baseline parathyroid hormone and vitamin D levels were also assessed. Multivariate regression models were used to investigate the relationship between the different variables and BMD.

Results: Thirty-six patients (45.6%) had low BMD at baseline. Factors correlating with the low BMD were older age, postmenopausal status, and tertiary hyperparathyroidism (P<0.0005, 0.009, and 0.027, respectively). There was a linear decrease in total hip and lumbar spine BMD from baseline to 12 months, the decrease from baseline to 6 months being significant (P=0.019 for total hip and P<0.0005 for lumbar spine). Patients with tertiary hyperparathyroidism had a greater risk of decrease in BMD at 6 months compared with patients with secondary hyperparathyroidism (odds ratio=13.5, confidence interval: 1.3, 144.4) and with those who had parathyroidectomy (odds ratio=34.9; confidence interval: 2.0, 598.8).

Conclusions: The prevalence of low BMD in this population of renal transplant recipients was high. Parathyroid status was the only independent factor that correlated with low BMD at baseline and subsequent bone loss highlighting the critical role of this hormone in bone metabolism after renal transplant.