Mineral metabolism, bone histomorphometry and vascular calcification in alternate night nocturnal haemodialysis.

Background: Poor control of bone mineral metabolism (BMM) is associated with renal osteodystrophy and mortality in dialysis-dependent patients. The authors explored the efficacy of alternate nightly home haemodialysis (ANHHD) in controlling BMM parameters and its effects on bone mineral density and histomorphometry.

Methods: In this prospective observational study, 26 patients on home haemodialysis (3-5 h, 3.5-4 sessions weekly) were converted to ANHHD (6-9 h, 3.5-4 sessions weekly). Biochemical parameters of BMM at baseline, 6 and 12 months, radiological parameters at baseline and 12 months and bone histomorphometry at 12 months are described.

Results: Pre-dialysis serum phosphate fell from 2.13+/-0.65 to 1.38+/-0.35 mmol/L; P<0.0001. No binders were required in 77.2% compared with 7.7% at baseline. Calcium-phosphate product fell from 5.28+/-1.64 to 3.42+/-0.88 mmol2/L2; P<0.0001 and parathyroid hormone (PTH) from 301 (110-471) to 127 (47-240) ng/L; P=0.01. Bone mineral density remained stable. Vascular and ectopic calcification improved or stabilized in 87.5%. Bone histomorphometry at 12 months showed high, normal and low bone turnover in 10, 3 and 4 patients, respectively, with 6/17 patients having abnormal mineralization.

Conclusion: Alternate nightly home haemodialysis effectively manages biochemical parameters of BMM. Patients with very high PTH at baseline (>1000 ng/L) did not significantly improve parathyroid hormone status. Abnormal bone turnover and mineralization were present in a significant proportion of patients at 12 months but low turnover was uncommon. Vascular calcification was stabilized or improved in the majority. ANHHD compares favourably with every night and short daily therapy in relation to BMM management and may offer lifestyle advantages for patients.