Estimated lean body mass is more appropriate than body surface area for scaling glomerular filtration rate and extracellular fluid volume.

BACKGROUND/AIMS: To compare body surface area (BSA) with lean body mass (LBM) for scaling extracellular fluid volume (ECV) and glomerular filtration rate (GFR). METHODS: Phase 1: Total body water (TBW), bromide space and LBM were measured with (3)H-water, (77)Br and dual X-ray absorptiometry, respectively, in 6 healthy adults. Phase 2: ECV and GFR were measured with (51)Cr-EDTA in 95 healthy adults and 56 children (0.5-13 years). ECV was calculated as GFR divided by GFR/ECV, both corrected for the one-compartment assumption. LBM was estimated (eLBM) in adults from height and weight and in children using a height/weight formula for estimating ECV and a constant derived from a separate adult population relating ECV to eLBM. RESULTS: Phase 1: LBM and BSA correlated closely with TBW and bromide space. With LBM, the regressions passed through the origin, but with BSA, the intercepts were significantly below zero. Phase 2: GFR/BSA and ECV/BSA were higher in men than women but no difference was recorded in GFR/eLBM, GFR/ECV or ECV/eLBM. ECV showed a linear relation with eLBM and a non-linear relation with BSA. GFR/BSA and ECV/BSA correlated significantly with BSA but neither GFR/eLBM nor ECV/eLBM correlated with eLBM. CONCLUSION: eLBM is preferable to BSA for scaling GFR and ECV.

Lack of effect of intravenous pamidronate on fracture incidence and bone mineral density after orthotopic liver transplantation.

BACKGROUND/AIMS: Increased rates of bone loss and fracture have been reported after liver transplantation. The aim of this study was to investigate the effects of a pre-transplant infusion of pamidronate on fracture incidence and bone loss during the first year after transplantation. METHODS: Ninety-nine adults awaiting orthotopic liver transplantation (OLT) were randomised to pamidronate or no treatment. Spinal X-rays were obtained at baseline and after 12 months. Bone mineral density (BMD) was measured at the lumbar spine (L1-4) and femoral neck at baseline, and 3, 6, and 12 months after OLT. RESULTS: The incidence of fractures in the first year after OLT was 8%, four patients within the pamidronate treated group and two in the untreated group developing fractures (P=0.40). No significant spinal bone loss occurred in either group during the first year. However, significant and sustained bone loss occurred at the femoral neck in both groups. No significant differences were seen between pamidronate treated or untreated groups at either site. CONCLUSIONS: Pamidronate in the regimen used had no significant effect on fracture rate or BMD post-transplant. The low incidence of fracture and absence of spinal bone loss indicate that bone disease after liver transplantation may be less common than previously reported.

Significant and persistent loss of bone mineral density in the femoral neck after haematopoietic stem cell transplantation: long-term follow-up of a prospective study.

Reduced bone mineral density (BMD) has been reported following allogeneic stem cell transplantation (alloSCT) but the effects of autologous SCT (autoSCT) are less well characterized. We performed a prospective study of BMD changes and its determinants in 44 SCT recipients (38 auto and six allo; 30 peripheral blood SCT and 14 bone marrow transplantation). Serial measurements of BMD at the lumbar spine and femoral neck were performed at baseline and at 3, 6, 12 and 24 months, and spinal radiographs were performed at baseline and 12 months. Mean baseline BMD values at the femoral neck and spine were within normal limits. At 3 months, there was a significant decline of BMD at the femoral neck (P = 0.011) and a non-significant trend towards reduction at the spine. BMD loss persisted for up to 2 years at the femoral neck (P = 0.005), but values returned to baseline at the spine. Reflecting the rapid initial decline in BMD, bone-specific alkaline phosphatase (a serum marker of bone formation) showed a significant initial decline at 1 month but had recovered to pretransplant levels by 3 months. No new fractures were detected at 1 year post transplant. Sex, diagnosis, use of total body irradiation, stem cell source and type of graft (auto versus allo) did not significantly predict BMD change over the first 12 months. In conclusion, significant and persistent bone loss at the femoral neck was demonstrated in this group of patients following stem cell transplantation. The implications of these findings for future fracture risk require further study.