Simple OST Beats FRAX for Osteoporosis Prescreening in Men

Veronica Hackethal, MD

August 24, 2017

A simple test called the Osteoporosis Self-Assessment Tool (OST) performs better than a more complicated, web-based Test Fracture Risk Assessment (FRAX) tool for selecting which older men to screen for osteoporosis, according to a study published online on August 16 in the Journal of General Internal Medicine.

"The take-home point from our study is that there are simple tools, mainly the OST, which can be used to select older men for testing for bone-mineral density [BMD]. These tools are very reasonable alternatives to universal screening of men for osteoporosis and are easier to use than FRAX," first author Susan Diem, MD, MPH, of the University of Minnesota, Minneapolis, told Medscape Medical News.

Worldwide, one in five men over age 50 years develop fractures related to osteoporosis, and the incidence increases with age. The National Osteoporosis Foundation, the Endocrine Society, and the American College of Physicians all recommend universal screening in men age 70 and older. However, the US Preventive Services Task Force (USPSTF) has said insufficient evidence exists to support universal screening, according to Dr Diem.

"That's certainly our impression," Dr Diem said, "There's still a significant lack of evidence to support universal screening at this time. It doesn't mean that universal screening may turn out to be the correct approach for men age 70 and older. But it also may be premature, given our serious gaps in knowledge about osteoporosis in men."

Potential harms of universal screening include increased healthcare costs and overtreatment, a particular concern given lack of evidence about the efficacy of treatment in men.

The prospective cohort study, called the Osteoporotic Fractures in Men (MrOS) study, included 4043 men aged 70 years and over. The men were from six regions of the United States; 90.8% were white.

Researchers measured BMD of the total hip, femoral neck, and lumbar spine using DXA scanning. They then compared how well OST performed compared with FRAX (without BMD) in distinguishing between men with and without osteoporosis. They also evaluated various cutoffs for these prescreening tools. For FRAX, the cutoff for recommendation for BMD testing is ≥9.3% 10-year risk of major osteoporotic fractures, according to USPSTF recommendations.

Results show that OST identified osteoporosis better than FRAX (without BMD), according to area-under-the-curve (AUC) calculations, with higher AUC indicating greater probability that a positive test is a true positive and a negative test is a true negative. (AUC 0.68 vs AUC 0.62; P = .004).

Results also indicate that using an OST cutoff <2 decreased the percentage of men who needed DXA screening, decreased false positives, and missed fewer cases of osteoporosis.

An OST threshold <2 had a sensitivity of 0.83 and specificity of 0.36 for identifying osteoporosis, while FRAX (without BMD) had a sensitivity of 0.59 and specificity of 0.59.

In 1000 men, using the OST cutoff <2 would result in 654 referred for BMD, and the test would identify osteoporosis in 44 of these men, missing nine.

OST is not the only tool developed to prescreen for osteoporosis in men. Another tool, called the Male Osteoporosis Risk Estimation Score (MORES), has also been developed and has also been found to perform better than FRAX.

Like OST, MORES relies on clinical risk factors alone but is slightly more complicated to calculate. MORES uses age, weight, and whether an individual has chronic obstructive pulmonary disease (COPD), while OST only needs age and weight, according to Dr Diem.  

The current study did not compare MORES and OST, so the results cannot distinguish which is better. It's safe to say, though, that OST and MORES probably are better prescreening tools than FRAX. And that OST is easier to use than MORES, according to Dr Diem.

"The findings with MORES are similar to our findings with OST, that age and weight are probably the two biggest things to take into account when trying to choose men to screen," she said. "One of the beauties of OST is that it's so easy to use. With MORES you have to add up points, whereas the OST is a very simple calculation."

The Osteoporotic Fractures in Men Study is supported by funding from the National Institutes of Health. Support is provided by the following: National Institute on Aging (NIA), National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), National Center for Advancing Translational Sciences (NCATS), and NIH Roadmap for Medical Research. Dr Diem has no relevant financial relationships. Disclosures for the coauthors are listed in the paper.

J Gen Intern Med. Published online August 16, 2017. Abstract

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