Comparison of the Humoral Markers of Bone Turnover and Bone Mineral Density in Patients on Haemodialysis and Continuous Ambulatory Peritoneal Dialysis

Abstract

Renal osteodystrophy is an important complication in patients with end-stage renal disease on maintenance dialysis. The aim of this study was to compare the biochemical markers of bone formation (serum collagen type I C-terminal propeptide) and resorption (serum deoxypyridinoline – DPD – and pyridinoline – PYR) with the bone mineral density (BMD) at lumbar spine, femoral neck, and forearm in patients with end-stage renal disease on haemodialysis (HD) versus continuous ambulatory peritoneal dialysis (CAPD). Fifty-nine adult patients, 45 on CAPD (18 females, 27 males) and 14 on HD (2 females, 12 males), were studied. The mean age was 44 ± SEM 1.6 and 54.4 ± 4.8 years, respectively. No significant differences in serum calcium, phosphorus, creatinine, and parathyroid hormone were found between patients on HD and CAPD in predialysis samples. Serum urea was significantly lower (p = 0.02) in the CAPD group. Serum PYR (nmol/l) and DPD (nmol/l) were significantly higher in patients on HD as compared with those on CAPD: 105 ± 23.3 versus 43.7 ± 3.47 (p = 0.007) and 31.0 ± 2.4 versus 24.4 ± 1.4 (p = 0.027), respectively. The results were still significantly higher in the HD patients following correction for serum creatinine and body mass index. There was a close correlation between dialysate DPD and creatinine in both dialysis modalities (HD r = 0.9, CAPD r = 0.76). The clearance of DPD did not differ significantly between the CAPD membrane and the HD membrane (p = 0.22). Serum collagen type I C-terminal propeptide was not significantly different between the HD and CAPD patients. The results were unaffected following correction for age and gender. The BMD was measured in 38 (65%) of the patients (HD n = 8, CAPD n = 30) by dual-energy X-ray absorptiometry and expressed as ‘Z’ scores. This was reduced at all sites in the patients with end-stage renal disease. The BMD was significantly lower at the ultradistal forearm (mostly trabecular bone) in HD patients as compared with CAPD patients (n = 0.02). A similar trend was observed at the lumbar spine, although the results failed to reach significance. In the whole population (n = 38), linear regression analysis revealed a significant negative correlation between BMD at the ultradistal forearm and serum PYR (r = –0.35, p = 0.04) and DPD (r = –0.33, p = 0.049). Combined measurements of BMD and biochemical markers of bone resorption may have potential in the identification of patients at high risk of bone loss who may require further evaluation of bone remodeling by bone histomorphometry.

Comparison of Biochemical Markers of Bone Turnover in Patients on Continuous Ambulatory Peritoneal Dialysis and Maintenance Hemodialysis

“…Obtained findings support the studies of Hampson et al (11). They found no significant differences in serum calcium, phosphorus and parathyroid hormone between patients on HD and CAPD.…”

“…Many authors (11,16) point at the relationship between serum levels of Ca and P with iPTH in patients on hemodialysis and continuous ambulatory peritoneal dialysis. Our results show similar correlation in the sense of a desirable increase of analysed serum markers levels after dialysis session.…”

“…In dialysed patients there are different prevalences of ABD depending on the dialysis type and duration of dialysis, and many studies have explained this relation (11,12).…”

Bone mineral density in patients on maintenance dialysis

“…Better preservation of bone mass was also suggested in another study comparing BMD of 45 patients on PD to 15 patients on HD and patients in CKD stage 5 treated conservatively [88]. Patients on HD had lower BMD at all measurement site (lumbar spine, femoral neck, distal and ultradistal radius) than patients on PD; however, the difference reached statistical significance only at the ultradistal radius.…”

Metabolismo mineral óseo en pacientes con enfermedad renal crónica: revisión sobre su fisiopatología y morbimortalidad

“…Se encontró que los marcadores de resorción ósea estaban más elevados en pacientes en hemodiálisis y la densidad mineral ósea más disminuida en antebrazo de pacientes en hemodiálisis, comparado con los de diálisis peritoneal (54) . Otros biomarcadores estudiados son la fosfatasa alcalina y la osteoprotegerina.…”