A "biomechanical" analysis of a previously taken pelvic or abdominal computed tomography (CT) scan is at least as accurate in assessing an individual's hip fracture risk as a dual-energy X-ray absorptiometry (DXA) scan, according to new research.

This accuracy of the hip bone-mineral density (BMD) T-score as measured by the biomechanical CT (BCT) analysis was consistent for all fracture-risk metrics and both sexes, researchers found in a retrospective case-cohort study of nearly 4,000 participants.

Further, combining the classifications of fragile femoral bone strength and hip osteoporosis from BCT data resulted in higher sensitivity than the standard hip/spine osteoporosis classification by DXA, with comparable specificity.

In people who are already having a CT done for some other reason, particularly those aged 65 or older, "we can now screen them for osteoporosis simultaneously, sparing them the need for a separate DXA scan," lead author Dr. Annette Adams, of Kaiser Permanente Southern California, told.

"This is significant," she added because if an individual is identified as having osteoporosis, they can receive care to reduce the risk of a fracture. Such care could include medication, taking calcium and vitamin D, regular exercise, and avoiding excessive tobacco and alcohol.

Screening of patients

The researchers used data on more than 111,000 Kaiser Permanente patients who were 65 or older and had had a DXA scan within three years of a CT scan and no hip fracture before either scan. From this population, they matched 1,959 patients who later experienced a first non-traumatic hip fracture with 1,979 who did not.

They note that BCT analysis of 86% of the available CT scans was successful and that the latter had been performed on 80 different CT scanners in 14 hospitals over a nine-year period, supporting "technical robustness in a broad clinical setting."

The authors concluded that if BCT analysis were routinely used in individuals over age 65 "who have an available hip CT when a recommended DXA test is either missing, not available or inconvenient such a 'second front' in osteoporosis screening, could appreciably increase the number of patients identified as being at high risk of hip fracture."

Dr. Timothy Ziemlewicz, a radiologist at the University of Wisconsin School of Medicine and Public Health, in Madison, told that osteoporosis screening rates are low, even in those eligible under U.S. Preventive Services Task Force guidelines.

"An add-on analysis of imaging data already available stands to improve these screening rates and also offer to screen to patients who are not covered within guidelines, but nevertheless have potential fracture risk," said Dr. Ziemlewicz, who was not involved in the study.