An economic analysis by a group of researchers from New York University School of Medicine found the most cost effective osteoporosis screening strategy: Start at age 55 and use five-year intervals, combining dual energy x-ray absorptiometry and quantitative CT. Consistent screening reduced the lifetime risk of a hip fracture to 12.8 percent in the simulated cohohort, according to a study published in Radiology.
“Our model showed that the addition of bone strength testing to currently existing DXA screening recommendations for postmenopausal women would be cost-saving compared with no screening (i.e., total cost of screening, prophylaxis, and treatment would be lower compared with no screening) and very cost-effective compared with DXA and use of the FRAX tool screening,” wrote lead author and former member of the Center For Musculoskeletal Care at NYU Langone Medical Center Christoph A. Agten, MD.
Osteoporosis is responsible for more than two million fractures every year in the U.S., inflicting high costs on the health system and creating disabilities with downstream societal impact. The most common clinical outcome is a pelvic fracture due to low bone mineral density, usually defined on DXA. However, most patients with fractures do not meet the DXA criteria for osteoporosis, indicating the low resolution of x-ray is impeding patient care, according to the authors.
Instead, advanced modalities like quantitative CT or MRI allow a bone strength estimate to be computed from bone images with a method called finite element analysis.
Study authors constructed a hypothetical cohort of one million menopausal women using modeling software. The simulated cohort was randomly assigned six risk factors used in the World Health Organizations fracture risk assessment tool, including smoking, family history of pelvic fracture, rheumatoid arthritis.
“The most cost-effective screening strategy was combined DXA/quantitative CT with screening initiation at age 55 and a quantitative CT screening interval of 5 years,” wrote Agten et al. “The total number of fractures with that strategy was substantially lower compared with that with DXA and that with no screening.”
The baseline rate of fracture with no screening was 18.7 percent, according to the study. Beginning DXA screening at 55 years of age reduced that percentage to 15.8 percent, but sprinkling in qualitative CT every five years further reduced the lifetime risk to 12.8 percent.
In addition, increasing the costs of CT within the predictive model didn’t substantially lower the cost-effectiveness of the screening strategy, demonstrating imaging practices have a little wiggle room before their return on investment dips into the red. This wiggle room includes substituting MRI for CT, according to the article.
“The overall most favorable screening strategy was combined DXA/quantitative CT at age 55 years with a five-year screening interval. With this strategy, the number of fragility fractures and the associated morbidity and mortality were substantially reduced,” wrote Agten et al.