Effects of parathyroidectomy on bone metabolism and bone mineral density in hemodialysis patients with secondary hyperparathyroidism

Abstract

Objective To observe the effects of parathyroidectomy(PTX) on bone metabolism and bone mineral density(BMD) in maintenance hemodialysis patients with secondary hyperparathyroidism (SHPT). Methods A total of 26 dialysis patients with SHPT were treated with PTX. Serum calcium, phosphorus, alkaline phosphatase(ALP) levels were determined by standard methods. The levels of serum intact parathyroid (iPTH), osteocalcin (OC), procollagen type I amino-terminal propeptide (PINP), β-crosslaps (β-CTX) were measured by chemiluminescence. BMD was measured by dual energy X ray absorptiometry. iPTH, OC, PINP, β-CTX, serum calcium, phosphorus, ALP were measured before parathyroidectomy and 1, 3, 6, 12, 18, 24 months after operation. Lumbar spine (LS) and femoral neck (FN) BMD were measured before and 24 months after PTX. Results Compared with that before operation, serum OC[(104.49±25.42) μg/L vs (695.46±355.62) μg/L, P<0.01] and PINP levels [(248.36±159.38) μg/L vs (809.28±283.50) μg/L, P<0.01] progressively decreased 3 months after PTX, and serum β-CTX levels [(1.60±0.64) μg/L vs (3.37±1.34) μg/L, P<0.01] decreased 1 month after PTX. Compared with that before operation, BMD levels increased 24 months after PTX in LS[(0.88±0.23) g/cm2 vs (0.78±0.23) g/cm2, P<0.01] and FN[(0.96±0.19) g/cm2 vs (0.84±0.24) g/cm2, P<0.01], and Z-scores were also increased in both LS[(-1.24±0.55) vs (-1.66±0.24), P<0.01] and FN[(-1.51±0.72) vs (-1.93±0.40), P<0.01]. Correlation analysis showed that baseline iPTH was positively correlated with ⊿Z-score in FN (r=0.584, P=0.002) and LS (r=0.400, P=0.043), and so did the OC with ⊿Z-score in FN (r=0.651, P<0.001) and LS (r=0.509, P=0.008). Conclusion The levels of OC, PINP and β-CTX are reduced and BMD is improved in hemodialysis patients with SHPT after PTX. Key words: Bone mineral density; Parathyroidectomy; Hyperparathyroidism, secondary; Hemodialysis; Bone metabolism