OBJECTIVES:To describe the prevalence of risk factors for women at high risk of fracture in a population-based sample of postmenopausal women who were not using hormone replacement therapy (HRT), to demonstrate how the estimated prevalence of women at high risk of future fracture is affected by the different criteria used for classification, and to characterize the populations identified and missed by each of the criteria. A key study objective was to compare the proportion of postmenopausal women at high risk of fracture in a managed care population using several different definitions of who is at high risk. DESIGN:The Osteoporosis Population-based Risk Assessment study, a randomized trial of three screening strategies. SETTING:Conducted at Group Health Cooperative in western Washington state. PARTICIPANTS:Women aged 60 to 79 who had not used HRT for at least 12 months were chosen at random. MEASUREMENTS:In one of the trial arms, 428 women had their bone mineral density (BMD) measured at the hip and spine (L1-L4) using dual energy x-ray absorptiometry. Minimum t scores and z scores at all sites were used for classification. Risk factors for fractures were assessed at the time of the BMD scan. RESULTS:Guidelines based on the Study of Osteoporotic Fractures classified 25.1% of the women as being at high risk of fracture, compared with 30.0% and 68.0% using World Health Organization (WHO) recommendations and National Osteoporosis Foundation guidelines, respectively. Classification based on low BMD alone (WHO) failed to include more than 50% of women who had already experienced a clinical fracture. CONCLUSIONS:Prevalence of women at high risk of fracture not using HRT varies notably depending on the criteria used for identification. The criteria used to identify women to target for primary and secondary prevention of osteoporotic fractures has major implications for population-based prevention strategies.

Background

The integration of bone density testing into well-designed fracture prevention programs that can be applied in populations has not been studied.

Objectives

We sought to compare the outcomes of 3 strategies for allocating bone density testing within an HMO-based fracture prevention program.

Research design

Women were randomly sampled and allocated to one of 3 groups: (1) a universal group, in which all were offered bone mineral density (BMD) testing (1986 contacted; 415 participated); 2) the SCORE group, in which women scoring > or = 7 on the SCORE questionnaire were invited for BMD testing (1940 contacted; 576 participated); and (3) the Study of Osteoporotic Fracture (SOF)-based group, in which women with > or = 5 hip fracture risk factors were invited for BMD testing (5342 contacted; 2176 participated).

Subjects

Women aged 60-80 not taking hormone therapy or osteoporosis medication were included.

Measures

Outcomes ascertained during 33 months of follow-up in all women contacted included initiation of osteoporosis treatment and hip and total fracture rates. Outcomes evaluated among all participants included changes in fracture risk factors, osteoporosis knowledge, and satisfaction with the program.

Results

Osteoporosis treatment rates did not differ among all women contacted but were slightly higher among trial participants in the universal and SCORE groups (21.1% and 20.2%, respectively; versus 16.7% in the SOF-based group (P value versus universal = 0.04). Among all women contacted, fracture rates were lowest in the universal group (74.11/1000) and differed significantly compared with the SCORE (99.44/1000; P = 0.009) and SOF-based groups (91.77/1000;P = 0.02). Knowledge about osteoporosis risk factors was highest in the universal group and lowest in the SOF-based group (P < 0.01).

Conclusions

The degree to which BMD testing was offered to women in a fracture prevention program significantly affected total fracture rates, change in some fracture risk factors, and knowledge about risk factors.

Objectives

To describe differences in osteoporosis risk factors and rates of fracture and antiresorptive therapy use in women who did and did not participate in an osteoporosis screening program.

Setting

Group Health Cooperative, a health maintenance organization in western Washington state.

Participants

A total of 9,268 women (aged 60-80) who were not using any antiresorptive therapy were invited to participate in an osteoporosis screening program. This study compares the 35% who participated with the 65% who did not.

Design

This observational cohort study of women invited to participate in a randomized, controlled trial of an osteoporosis screening program provided all participants with personalized feedback on their risk of osteoporosis. Some participants also received bone density testing. Automated administrative data were used to examine differences between participants and nonparticipants in fracture outcomes and medication initiation before and after invitation.

Results

Baseline fracture rates did not differ between participants and nonparticipants. After age adjustment, nonparticipants had a higher hip fracture rate (14.1 vs 8.3 per 1,000) and a lower rate of initiating any antiresorptive therapy (10.3 vs 17.9 per 100) than participants after an average of 28 to 29 months of follow-up.

Conclusion

Participants had reduced hip fracture rates and increased initiation of antiresorptive therapy compared with nonparticipants. It was not possible to determine whether participating in the screening program, unmeasured confounding, or selection bias accounted for differences in hip fracture or therapy initiation rates. These results suggest that women who do not participate in osteoporosis screening should be pursued to identify individuals who could benefit from primary and secondary osteoporosis prevention.

Decision rules for intervention that utilize screening tools for bone mineral density (BMD) testing and incorporating the BMD findings and other risk factors to identify high-risk women to prevent fracture have not been evaluated. We examine the sensitivity and specificity of decision rules for intervention based on two pre-BMD screening tools: Simple Calculated Osteoporosis Risk Estimation (SCORE) and a Study of Osteoporotic Fractures (SOF)-based tool. Women 60 years of age and older without previous osteoporosis diagnosis were randomly selected from a managed care population and invited to receive a BMD test. Four hundred sixteen women had complete information and were included in the study. Women were classified as high risk requiring intervention using three different criteria: World Health Organization (t-score -2.5 or less), National Osteoporosis Foundation (t-score -2.0 or less, or -1.5 or less with one or more risk factors), and the SOF-based criteria (prior fracture; or age 60-64 with t-score less than -2.5 or age 65 or older with z-score less than -0.43 and five or more risk factors). SCORE identified 82% of the women as appropriate for BMD testing, whereas the SOF-based tool identified 26%. Sensitivity and specificity were 89.8%-96.5% and 23.8%-34.8%, respectively, for the decision rule using SCORE as the screening tool and 30.5%-84.9% and 76.0%-95.8%, respectively, for the decision rule based on SOF screening criteria. SCORE correctly identified more women who were at high risk for intervention, whereas the SOF-based tool correctly identified more women who do not meet intervention criteria. The appropriate selection of a screening tool depends upon the objective for intervention and trade-off between not identifying women for BMD testing who are at high risk and identifying more women for BMD testing who are at low risk.