Clinical question
What is the most efficient way to determine which patients are at a high risk of osteoporosis and require bone mineral density (BMD) testing?
Bottom line
The Osteoporosis Self-Assessment Tool (OST) is simple and quick, and predicts osteoporosis as reliably as other more complicated instruments. It is a reasonable screening tool to identify those who would benefit from BMD testing.
Evidence
A study of 860 postmenopausal Asian women examined 11 risk factors to predict osteoporosis1:
Multiple risk factors had minimal value over age and weight alone.
The OST was developed based on weight and age.
Eight systematic reviews were conducted from 2007 to 2015, with up to 108 studies and 208 738 patients evaluating more than 9 tools to assess the risk of osteoporosis or fractures.2–9
The OST performed at least as well as other tools.2–9
For example:
-The OST performs moderately well at identifying femoral neck osteoporosis (sensitivity 89%, specificity 41%) in postmenopausal white women.9
Tools with fewer risk factors (eg, OST) predict osteoporosis as well as or better than those with more factors.3,4,7–9
Unlike other tools to assess the risk of osteoporosis, the OST has been validated in both sexes and in several races.6,9
Context
The 2010 Osteoporosis Canada guidelines recommend detailed history taking and focused physical examinations for all patients aged 50 to 64 years, including assessment of 10 different risk factors for osteoporosis.10
The time required to fully satisfy preventive recommendations is prohibitive.
-For example, physicians need 7.4 hours per working day to provide preventive services alone.11
Application of the OST is simple: weight (in kg) minus age (in years).
-If the score is less than 10, there is an increased risk of osteoporosis and BMD testing is warranted.
-If the score is 10 or greater, there is a low risk (< 5%) of osteoporosis and BMD testing is not required.
Implementation
For practices with organized screening programs, the OST can be done at the administrative level. Websites12–14 and charts15 are available to help with OST screening. A simplified version uses weight (in kg) minus age (in years) and if the score is 10 or greater, then the person has a low risk of osteoporosis. Patients should weigh more than their age by at least 10 kg to have a low risk. For example, a 55-year-old woman weighing 70 kg has an OST score of 70 − 55 = 15. She has a low risk of osteoporosis and does not need BMD testing. A 60-year-old woman weighing 60 kg has an OST score of 60 − 60 = 0. She has an increased risk of osteoporosis and should be offered BMD testing.
Notes
Tools for Practice articles in Canadian Family Physician (CFP) are adapted from articles published on the Alberta College of Family Physicians (ACFP) website, summarizing medical evidence with a focus on topical issues and practice-modifying information. The ACFP summaries and the series in CFP are coordinated by Dr G. Michael Allan, and the summaries are co-authored by at least 1 practising family physician and are peer reviewed. Feedback is welcome and can be sent to toolsforpractice{at}cfpc.ca. Archived articles are available on the ACFP website: www.acfp.ca.
Footnotes
The opinions expressed in Tools for Practice articles are those of the authors and do not necessarily mirror the perspective and policy of the Alberta College of Family Physicians.
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