Randomized trial of once-weekly parathyroid hormone (1-84) on bone mineral density and remodeling.
BACKGROUND
Daily PTH administration increases bone mineral density (BMD) and reduces fracture risk. However, cost and compliance significantly limit clinical use.


OBJECTIVE
Our objective was to determine whether less frequent PTH administration increases lumbar spine BMD.


METHODS
Fifty postmenopausal women ages 45-70 yr with femoral neck BMD T-score between -1.0 and -2.0 participated in a double-blind, randomized, placebo-controlled trial at St. Joseph Hospital, Bangor, ME.


METHODS
Subjects received sc injections of daily PTH(1-84) (100 mug) or placebo for 1 month, followed by weekly injections (PTH or placebo) for 11 months.


RESULTS
Change in lumbar spine dual-energy x-ray absorptiometry areal BMD (primary) was assessed. Secondary outcomes included volumetric BMD at spine and hip by quantitative computed tomography, trabecular bone microarchitecture by magnetic resonance imaging of distal radius, and biochemical bone turnover markers.


RESULTS
At 12 months, lumbar spine areal BMD increased 2.1% in PTH-treated women compared with placebo (P = 0.03). Vertebral trabecular volumetric BMD increased 3.8% in PTH-treated women compared with placebo group (P = 0.08). PTH-treated women also had higher distal radial trabecular bone volume, number, and thickness compared with placebo-treated women (P < 0.04). After 1 month of daily PTH, N-terminal propeptide of type I collagen (P1NP) was markedly increased compared with placebo (P < 0 .0001), and a difference persisted, although lessened, throughout the study. Bone resorption indices were unchanged in PTH-treated women and were reduced in the placebo group.


CONCLUSIONS
Once-weekly PTH after 1 month of daily treatment increases spine BMD, radial trabecular bone, and bone formation markers in postmenopausal women. These results suggest that less frequent alternatives to daily PTH dosing for 2 yr could be effective. Additional studies are required to define the optimal frequency of PTH administration.
Black
Dennis M
DM
Department of Epidemiology and Biostatistics, University of California-San Francisco, 185 Berry Street, San Francisco, CA 94107, USA. dblack@psg.ucsf.edu
Bouxsein
Mary L
ML
Palermo
Lisa
L
McGowan
Joan A
JA
Newitt
David C
DC
Rosen
Eyal
E
Majumdar
Sharmila
S
Rosen
Clifford J
CJ
D000368:Aged; D000465:Algorithms; D015519:Bone Density / Q000187:drug effects*; D050071:Bone Density Conservation Agents / Q000008:administration & dosage; D016723:Bone Remodeling / Q000187:drug effects*; D002118:Calcium / Q000097:blood; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D005260:Female; D005269:Femur / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D006615:Hip / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D006801:Humans; D008875:Middle Aged; D015663:Osteoporosis, Postmenopausal / Q000188:drug therapy*; D010281:Parathyroid Hormone / Q000008:administration & dosage*; D010919:Placebos; D011859:Radiography; D013131:Spine / Q000000981:diagnostic imaging / Q000187:drug effects
D050071:Bone Density Conservation Agents; D010281:Parathyroid Hormone; D010919:Placebos; D002118:Calcium