RESEARCH - Vertebral strength changes in RA patients treated with alendronate

[Guest guest]

Arthritis Rheum. 2008 Oct 30;58(11):3340-3349.

Vertebral strength changes in rheumatoid arthritis patients treated

with alendronate, as assessed by finite element analysis of clinical

computed tomography scans: A prospective randomized clinical trial.

Mawatari T, Miura H, Hamai S, Shuto T, Nakashima Y, Okazaki K,

Kinukawa N, Sakai S, Hoffmann PF, Iwamoto Y, Keaveny TM.

Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan.

OBJECTIVE: Finite element analysis of clinical computed tomography

(CT) scans provides a noninvasive means of assessing vertebral

strength that is superior to dual x-ray absorptiometry (DXA)-measured

areal bone mineral density. The present study was undertaken to

compare strength changes, measured using this newer method, in

rheumatoid arthritis (RA) patients who were treated with alendronate

(ALN) versus those who were not.

METHODS: Thirty female RA patients without radiologic signs of L3

compression fractures or a history of osteoporosis medication were

enrolled in a prospective randomized clinical trial. Patients were

randomly assigned to the ALN group (5 mg orally, once daily) or the

control group not receiving antiresorptive treatment. All patients

were evaluated by DXA and quantitative CT at baseline and reevaluated

after a mean of 12.2 months. Nonlinear finite element analysis was

performed on the CT scans (n = 29 available for analysis) to compute

an estimate of vertebral compressive strength and to assess strength

changes associated with changes in the trabecular compartment and the

outer 2 mm of bone (peripheral compartment).

RESULTS: On average, vertebral strength was significantly decreased

from baseline in the control group (n = 15) (median change -10.6%; P =

0.008) but was maintained in the ALN group (n = 14) (median change

+0.4%; P = 0.55), with a significant difference between the 2 groups

(P < 0.01). Strength decreased more rapidly within the trabecular

bone, and ALN treatment was much more effective in the peripheral than

the trabecular compartment.

CONCLUSION: Our results indicate that patients with RA can lose a

substantial amount of vertebral strength over a relatively short

period of time, and this loss can be prevented by ALN, primarily via

its positive effect on the outer 2 mm of vertebral bone.

PMID: 18975334

http://www.ncbi.nlm.nih.gov/pubmed/18975334

Not an MD