Search for secondary osteoporosis: are Z scores useful predictors?
OBJECTIVE
To determine whether Z scores can be used to predict the likelihood of patients having a secondary cause of low bone mineral density.


METHODS
A retrospective cross sectional study was conducted among 136 consecutive patients with osteoporosis at Ninewells Hospital, Dundee, UK, between 1998-2002.


RESULTS
20.5% of female patients in this study were identified with previously unrecognised contributors to the low bone mineral density. In women, at a Z score cut-off of -1, the sensitivity of detecting a secondary cause for osteoporosis is 87.5% with a positive predictive value of 29.2%.


CONCLUSIONS
In women, a Z score of -1 would identify a majority of patients with a secondary cause for low bone mineral density and identifies patients who would especially benefit from a thorough history and clinical examination.
Swaminathan
K
K
Department of Endocrinology, Ninewells Hospital, Dundee, UK. krishnan.swaminathan@nhs.net
Flynn
R
R
Garton
M
M
Paterson
C
C
Leese
G
G
D015519:Bone Density / Q000502:physiology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010024:Osteoporosis / Q000209:etiology* / Q000503:physiopathology; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods; D012680:Sensitivity and Specificity