Opportunistic detection of osteoporosis

December 7, 2020
Bob Kronemyer

Freelance writer for Contemporary OB/GYN

A Chinese study found that low‐dose computed tomography (LDCT) imaging is a viable alternative to standard dual‐energy X‐ray absorptiometry (DXA) scans for the opportunistic screening of osteoporosis.

osteoporosis.

The study, published in the Journal of Bone and Mineral Research, evaluated the computed tomography (CT)‐derived bone mineral density (BMD) and prevalence of osteoporosis from thoracic LDCT in a large population-based cohort of Chinese men and women.

“CT scans of the chest and abdomen are commonly performed for a wide variety of clinical indications,” said principal investigator Wei Tian, MD, PhD, an academician of the Chinese Academy of Engineering (CAE) and a professor of spine surgery at Beijing Jishuitan Hospital in China. “Incidental but robust screening data for osteoporosis are present on all of these CT scans but are often not used. We propose to use this ‘opportunistic’ screening data in a more systematic way.”

A total of 69,095 adults (40,733 men and 28,362 women) received a thoracic LDCT scan for the purpose of lung cancer screening in 2018 or 2019.

Data were obtained for analysis from the China Biobank Project, a prospective nationwide, multicenter population study.

Lumbar spine trabecular volumetric BMD (vBMD) was derived from the LDCT scans via quantitative computed tomography (QCT) software and diagnostic criteria for osteoporosis from the American College of Radiology’s diagnostic criteria for osteoporosis.

The population frequency of osteoporosis in Chinese men and women was estimated from the 2010 China census.

The percentage of women with osteoporosis increased from 2.8% at age 50 to 54 years to 79.8% at age 85 years and above.

In men, the prevalence of osteoporosis was 3.2% at age 50 to 54 years and 44.1% at age 85 years and above.

Overall, the pervasiveness of osteoporosis by QCT for the Chinese population aged under 50 years was 29.0% for women and 13.5% for men, equating to 49.0 million and 22.8 million, respectively.

In women, this rate is comparable to DXA estimates, but in men the prevalence is double.

Frequency varied geographically, with higher rates in the southwest and lower rates in the northeast areas of China.

In addition, trabecular vBMD significantly decreased with age, in both men and women.

Women had higher peak trabecular vBMD (185.4 mg/cm3) than men (176.6 mg/cm3) at age 30 to 34 years. But at 80, women had lower trabecular vBMD (62.4 mg/cm3) than men (92.1 mg/cm3).

“We show that LDCT‐based opportunistic screening for osteoporosis can identify large numbers of patients with low lumbar vBMD,” Tian told Contemporary OB/GYN. “However, while the CT results for osteoporosis were similar to DXA for women, we were surprised to discover that the rates for men were much higher on CT versus DXA estimates.”

DXA is a planar technique with a number of drawbacks, according to Tian, including low sensitivity and BMD results that are impacted by body weight and spine degenerative change. “CT provides a more direct volumetric measure and is likely a more accurate method for BMD assessment,” he said.

Going forward, Tian believes the study’s opportunistic measures must be further implemented and confirmed in more diverse patient populations.

“We are seeing greatly increased interest in using opportunistic CT screening for osteoporosis,” he said. “Such a combination would likely be cost-effective and clinically efficacious in fracture prevention and supporting national health economic analyses.”

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Disclosures

Tian reports no relevant financial disclosures.

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Reference

  1. Cheng X, Zhao K, Zha X, et al. Opportunistic screening using low‐dose CT and the prevalence of osteoporosis in China: a nationwide, multicenter study. JBMR. Published online November 4, 2020. doi:org/10.1002/jbmr.4187