RESEARCH - Effects of bisphosphonates on fracture incidence and bone metabolism in RA patients taking long-term steroids

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Effects of Bisphosphonates on Fracture Incidence and Bone Metabolism

in Rheumatoid Arthritis Patients in General Practice Taking Long-Term

Corticosteroid Therapy: A Retrospective Study.

Original Research Article

Clinical Drug Investigation. 28(3):149-158, 2008.

Katayama, Kou 1 2; Matsuno, Takeo 2

Abstract:

Background: and objective: There is a risk that disturbances of

activities of daily living (ADL) due to rheumatoid arthritis (RA) are

increased by the occurrence of fractures, including vertebral

compression fractures and femoral neck fractures, in RA patients

receiving oral corticosteroid therapy. Bisphosphonates are most

commonly used in the treatment of postmenopausal osteoporosis. In a

large-scale, randomized, double-blind, placebo-controlled study that

was performed to assess the prophylactic efficacy of bisphosphonates,

alendronic acid decreased the incidence of vertebral fractures by

approximately 50% compared with placebo in postmenopausal patients. A

similar result has also been reported with risedronic acid. The

present long-term retrospective study evaluated the effects of

alendronic acid and risedronic acid therapy on development of new

vertebral/non-vertebral fractures in RA patients receiving long-term

oral prednisolone therapy at an average dose of 5 mg/day.

Methods: The subjects were 138 general practice patients aged 50-79

years with RA (alendronic acid group 80; risedronic acid group 58) who

received oral prednisolone at a dose of 2-15 mg/day for at least 1

year combined with bisphosphonate therapy (alendronic acid 5 mg/day or

risedronic acid 2.5 mg/day) for at least 10 months. Patients with five

or more vertebral fractures at the start of bisphosphonate therapy

were excluded from the study. Vertebral fractures were detected by

obtaining plain x-ray films of the thoracic and lumbar spines at the

start of bisphosphonate therapy and on completion of follow-up. We

measured the incidence of new fractures, the speed of sound (SOS) at

the calcaneus as measured by quantitative ultrasound, and levels of

crosslinked N-telopeptide of type I collagen (NTX), a marker of bone

resorption. The percentage change at each measuring point was tested

using the paired t-test. The incidence of new fractures was compared

between groups using the proportional hazard model.

Results: The incidence of new vertebral fractures was 6.3% in the

alendronic acid group and 13.8% in the risedronic acid group; the

incidence of new non-vertebral fractures was 6.3% and 12.1%,

respectively. The incidence of any fracture was significantly higher

and severe fractures tended to be more common in the risedronic acid

group. Analysis by the proportional hazard model revealed a

significant difference between the two groups with respect to the

cumulative incidence of new fractures (p = 0.0386). The SOS of the

calcaneus showed no appreciable difference between the two groups. NTX

measurements indicated that antiresorptive activity was maintained

from 6 months of treatment onwards in the alendronic acid group but

not in the risedronic acid group.

Conclusion: These findings suggest that alendronic acid has a stronger

prophylactic effect against fractures than risedronic acid in RA

general practice patients taking long-term corticosteroid therapy.

http://druginvestigation.adisonline.com/pt/re/dri/abstract.00044011-200828030-00\

002.htm

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Not an MD