Background. Glucocorticoids may increase bone fragility via mechanisms inde
pendent from their bone mass reducing effect. Objective. To study relations
hips between osteoporotic fractures and bane mineral density in patients on
long-term glucocorticoid therapy. Patients and methods. We studied 121 wom
en with a mean age of 60.4+/-14.3 years on long-term glucocorticoid therapy
(cumulative dose greater than or equal to 1 g of prednisone equivalent, du
ration greater than or equal to 6 months) for rheumatoid arthritis (n = 38)
, polymyalgia rheumatica or giant cell arteritis (n = 26), connective tissu
e disease (n = 15), asthma (n = 14), another inflammatory joint disease (n
= 14), or another condition (n = 14). The control group was composed of 125
subjects who had the same mean age and met the same exclusion criteria as
the case group. Bone mineral density was measured at the lumbar spine and f
emoral neck using a Hologic QDR 4500(R) unit. In subjects with back pain, r
adiographs of the thoracic and lumbar spine were obtained to look for fract
ures. Results. The odds ratio far a bone mineral density decrease of one st
andard deviation at the femoral neck was 1.68 (1.20-2.35) in patients with
a cumulative glucocorticoid dose of 10 g of prednisone equivalent and 1.67
(1.22-2.29) in those with a glucocorticoid therapy duration of 2 years. Six
ty-eight fractures were recorded in 56 patients (46% of the overall patient
group). Even after adjustment on age, glucocorticoid therapy duration, and
dose, mean bone mineral density values at the lumbar spine and femoral nec
k were significantly lower in the subgroup of patients with fractures than
in the subgroup without fractures. Sensitivity and specificity of bone mine
ral density at the femoral neck and/or lumbar spine for the diagnosis of ve
rtebral fracture and/or peripheral fracture were 73% and 51%, respectively.
In the stepwise logistic regression model, factors explaining the presence
of fractures were as follows, in hierarchical order: age, absence of calci
um/vitamin D supplementation, femoral neck T-score, and glucocorticoid dose
. Conclusion. Our data are compelling evidence that bone mineral density is
a major determinant of the fracture risk in patients with glucocorticoid-i
nduced osteoporosis. (C) 2000 Editions scientifiques et medicales Elsevier
SAS.