Evaluation of decision rules for referring women for bone densitometry by dual-energy x-ray absorptiometry.
BACKGROUND
Identification of women with low bone mineral density (BMD) is an important strategy in reducing the incidence of osteoporotic fractures. However, screening all women is not recommended.


OBJECTIVE
To assess the diagnostic properties of 4 decision rules--Simple Calculated Osteoporosis Risk Estimation (SCORE), Osteoporosis Risk Assessment Instrument (ORAI), Age, Body Size, No Estrogen (ABONE), and body weight less than 70 kg (weight criterion)--for selecting women for dual-energy x-ray absorptiometry (DXA) testing and to compare results with recommendations made in the National Osteoporosis Foundation (NOF) practice guidelines.


METHODS
Analysis of data from the Canadian Multicentre Osteoporosis Study, a population-based community sample, collected from 9 study centers across Canada between February 1996 and September 1997.


METHODS
Postmenopausal women aged 45 years or older (N = 2365) without bone disease who had DXA data for the femoral neck, data to apply selection criteria, and who were not currently taking estrogens or who had been taking hormone replacement therapy for 5 or more years.


METHODS
Sensitivity, specificity, and area under the receiver operating characteristic (AUROC) curve of each of the 4 decision rules and the NOF guidelines for identifying women with a BMD T score of less than -1.0 SD, less than -2.0 SD, and no more than -2.5 SD at the femoral neck, and percentages of women recommended for testing, stratified by BMD level and age.


RESULTS
The percent of women with a BMD T score less than -1, less than -2, and no more than -2.5 were 68.3%, 25.4%, and 10.0%, respectively. The AUROC curves were greatest using SCORE and ORAI. The sensitivity for identifying women with a BMD T score of less than -2.0 was 93.7% (95% confidence interval [CI], 91.8%-95.6%) using the NOF guidelines and was 97.5% (95% CI, 96.3%-98.8%), 94.2% (95% CI, 92.3%-96.1%), 79.1% (95% CI, 75.9%-82.3%), and 79.6% (95% CI, 76.4%-82.8%), respectively, using the SCORE, ORAI, ABONE, and weight criterion. However, the NOF guidelines also resulted in 74.4% (95% CI, 71.3%-77.6%) of women with a normal BMD (T score of -1.0 or higher) being tested compared with 69.2% (95% CI, 65.9%-72.5%), 56.3% (95% CI, 52.7%-59.8%), 35.8% (95% CI, 32.4%-39.2%), and 38.1% (95% CI, 34.6%-41.6%), respectively, using the 4 decision rules. Assessments suggest that ABONE and weight criterion are not useful case-finding approaches.


CONCLUSIONS
The SCORE and ORAI decision rules are better than the NOF guidelines at targeting BMD testing in high-risk patients. The acceptability of these rules in clinical practice merits further investigation given their potential effect on the use of densitometry services.
Cadarette
S M
SM
Osteoporosis Research Program, Women's College Ambulatory Care Centre, Sunnybrook and Women's College Health Sciences Centre, 76 Grenville St, 10th Floor E, Room 1005, Toronto, Ontario, Canada M5S 1B2. s.cadarette@utoronto.ca
Jaglal
S B
SB
Murray
T M
TM
McIsaac
W J
WJ
Joseph
L
L
Brown
J P
JP
D015502:Absorptiometry, Photon; D000368:Aged; D015519:Bone Density; D003661:Decision Support Techniques; D005260:Female; D005272:Femur Neck / Q000000981:diagnostic imaging; D006801:Humans; D008875:Middle Aged; D010024:Osteoporosis / Q000517:prevention & control*; D017698:Postmenopause; D017410:Practice Guidelines as Topic; D012017:Referral and Consultation / Q000592:standards*; D018570:Risk Assessment; D012680:Sensitivity and Specificity