The effect of raloxifene after discontinuation of long-term alendronate treatment of postmenopausal osteoporosis.
OBJECTIVE
The aim of this study was to compare bone mineral density (BMD) and biochemical markers of bone turnover in patients receiving long-term alendronate therapy who continued alendronate, were switched to raloxifene, or discontinued antiresorptive therapy.


METHODS
Ninety-nine ambulatory women who were diagnosed with postmenopausal osteoporosis and treated with alendronate (10 mg/d) for a mean period of 43 months were randomized to double-blind raloxifene (60 mg/d; n = 33), placebo (n = 33), or continuation of open-label alendronate (n = 33) for 12 months. Patients continued their assigned treatment in a subsequent 12-month, open-label extension phase. All patients received supplemental calcium (500 mg/d) and vitamin D (800 IU/d).


METHODS
BMD (lumbar spine, total femur, femoral neck, distal forearm, and total body) and biochemical markers (serum intact amino-terminal propeptide of type I procollagen, type 1 collagen cross-linked C-telopeptide, and osteocalcin) were measured at baseline and follow-up visits.


RESULTS
Discontinuation of alendronate therapy resulted in a decrease in lumbar spine BMD at 12 months (-2.66%; P < 0.05), but did not change total femur BMD (+0.35%; nonsignificant). Raloxifene and alendronate, compared with discontinuation, prevented lumbar spine BMD loss (-0.75% and -0.54% at 12 months, respectively; P < 0.05). Raloxifene and alendronate caused a similar increase in total femur BMD at 12 months (1.45% and 1.56%; both P < 0.05 vs. baseline; nonsignificant vs. discontinuation). Patients, who discontinued alendronate therapy experienced an increase in bone turnover. Bone turnover increases were less pronounced in patients taking raloxifene and were absent in those who continued alendronate. Of the three groups, mean bone turnover in raloxifene patients was the closest to premenopausal mean values.


CONCLUSIONS
BMD preservation and increase were most pronounced in patients continuing alendronate. Raloxifene treatment, compared with placebo, demonstrated beneficial effects on BMD and bone turnover after discontinuation of long-term alendronate therapy.
Michalská
Dana
D
Third Department of Internal Medicine, Charles University, Faculty of Medicine, U Nemocnice 1, 128 00 Prague, Czech Republic.
Stepan
Jan J
JJ
Basson
Bruce R
BR
Pavo
Imre
I
D019386:Alendronate / Q000008:administration & dosage / Q000627:therapeutic use*; D050071:Bone Density Conservation Agents / Q000627:therapeutic use; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D008875:Middle Aged; D015663:Osteoporosis, Postmenopausal / Q000188:drug therapy*; D010919:Placebos; D020849:Raloxifene Hydrochloride / Q000008:administration & dosage / Q000627:therapeutic use*
D050071:Bone Density Conservation Agents; D010919:Placebos; D020849:Raloxifene Hydrochloride; D019386:Alendronate