Author/Authors :
Rajaei، Alireza نويسنده , , Dehghan، Pooneh نويسنده Department of Imaging, Research Development Center,
Taleghani Hospital, Shahid Beheshti University of Medical Sciences,
Tehran, Iran , , Ariannia، Saideh نويسنده Department of Rheumatology, Loghman e Hakim Hospital,
Shahid Beheshti University of Medical Sciences, Tehran,
Iran , , Ahmadzadeh، Arman نويسنده Dept. of Rheumatology, Shahid Beheshti University of Medical Sciences, Tehran , , Shakiba، Madjid نويسنده , , Sheibani، Kourosh نويسنده Clinical Research and Development Center, Imam Hossein Medical Center, Shahid Beheshti Univer-sity of Medical Sciences, Tehran, Iran ,
Abstract :
Using the same cutoff points for whole-body measurements as for
site-specific measurements will result in underestimation of
osteoporosis. We assessed the correlation between densitometry
measurements for the whole body with those for the femur, lumbar spine,
and forearm to evaluate the possibility of replacing site-specific
values with whole-body measurements. In this cross-sectional study, we
evaluated all patients referred to a single rheumatology clinic for bone
mineral density measurements from 2009 to 2010. All patients who had
bone mineral density measurements taken from the hip, lumbar spine,
forearm, and whole body were enrolled in the study. Standard bone
mineral density measurements were performed using a dual energy X-ray
absorptiometry device (Hologic Delphi A; Hologic, Bedford, MA, USA).
Bone mineral density, Z-score, and T-score were measured for all
patients and all body regions. The mean age of the 152 participating
patients was 56.7 ± 12.6 years, and 97.4% were female. Pearson
correlation coefficients of the whole-body bone mineral density values
compared with site-specific values in patients over age 50 were 0.66 –
0.75. Using T-score cutoff points of -1 and -2.5 for osteopenia and
osteoporosis, whole-body measurements underestimated the percentage of
abnormal patients compared with the site-specific measurements (all P
< 0.001). Using receiver operating characteristic (ROC) analysis,
the whole-body bone mineral density showed respective areas under the
curve of 0.96 and 0.84 for the diagnosis of abnormal hip bone mineral
density and osteoporosis. Using the same cutoff points for whole-body
measurements as for site-specific measurements will result in
overestimation or especially underestimation of osteopenia and
osteoporosis diagnosis. Choosing new and appropriate cutoff points for
whole-body densitometric measurements when we want to substitutes this
assessment instead of site specific measurements seems mandatory and
will decrease the rate of false diagnoses of densitometric deficiencies
in these anatomical sites.
