Abstract
Background and Aims
Chronic kidney disease patients get affected by mineral bone disease in view of changes in various biochemical parameters. After transplantation there are changes in these parameters with additional effect of immunosuppression on bone mineral density. My study was to observe changes in biochemical parameters like calcium, phosphorus, vitamin D, parathyroid hormone, alkaline phosphatase and compare bone mineral density with the help of DEXA scan post renal transplantation after 3 and 6 months. It was a prospective observational comparative study.
Aim of my study is to evaluate changes in Bone Mineral Density post renal transplantation
Method
Study was conducted at Apollo Tertiary care Hospital, Hyderabad which caters to rural as well as urban population in southern parts of India. This study was carried out form June 2017 to Dec 2018. Total 40 patients were included in study and they were followed up for the period of 6 months and underwent sets of investigations to assess their bone mineral density. Biochemical variables consist of calcium, phosphorus, alkaline phosphatase, vitamin D level and iPTH. Biochemical variables were classified into hypo, normal or hyper based on their lab values. iPTH values were considered high if value was nine times the upper limit of normal or low if value was less than two times the upper limit of normal. DEXA scan results were classified into normal, osteopenia and osteoporosis based on their t value.
Results
Study showed that patients who got admitted for transplant belong to age group of 31 – 50 yrs (39.8 +/- 12.8 yrs) predominantly male patients 30 (75%). In 25% patients (10) we were unable to find out native kidney disease shown as CKD (u). Other common causes were DM, ADPKD, CGN or CIN. Most patients were undergoing dialysis for more than 1 year, 47.5% (19) had significant loss of BMD as compared to patients whose dialysis was <1 year (p value 0.498 and 0.05). Hypocalcemia was predominantly seen in pretransplant period 26 (65%) but as the patient followed up level improved with few developing hypercalcemia 4 (10%) after 6 months. Hyperphosphotemia was seen in 19 (47.5%) patients before transplant while hypophosphatemia in 4 (10%) patients 6 months post transplantation, others had normal phosphorus level. Patients were on calcium and vitamin D supplements developed sufficiency to high level of vitamin D 33 (82.5%) patients 6 months post renal transplant. In iPTH around 12 (30%) of patients were having iPTH >150 pg/dl after 6 months of transplant. Majority presented for transplant detected to have osteoporosis and osteopenia at lumbar spine 31 (77.5%) and hip joint 27 (67.5%) with fracture risk 4 to 8 times of normal population. There was 8% and 10% increase in number of patients having osteoporosis at lumbar spine and hip joint respectively post-transplant. There was loss of 5.5% (mean t score at 0 month -1.98 and at 6 month -2.09) BMD at lumbar spine and 1.7% (mean t score at 0 month -1.83 and at 6 month -1.9) BMD at hip joint. Net loss of BMD was 3.6% over the period of 6 months. This accounts to increased risk of fractures post renal transplant. Biochemical variable in the form of iPTH has shown to have significant association with DEXA scan at lumbar spine (p value 0.01) and hip joint (p value 0.00) before and after transplant (p value of 0.01 and 0.00) though there was fall in iPTH level.
Conclusion
Pretransplant bone disease remains predominant cause of post-transplant bone disease with significant association with iPTH. Hypophosphatemia, hypercalcemia and high Vitamin D level are common findings in post-transplant period upto 6 months. Early use of DEXA scan along with follow up of biochemical variables can help to prognosticate and decide treatment strategies to reduce fracture risk in renal transplant recipients.
Correlation Between Bone Density and Lumbar Compression Fractures
