Utilization and reporting of bone densitometry: what can the musculoskeletal radiologist do to help, rather than to hurt?

Dual-energy X-ray Absorptiometry Trends Among US Medicare Beneficiaries: 2005-2019

INTRODUCTION

Bone density measured using dual-energy X-ray absorptiometry (DXA) volume, performance site and interpreters have changed in the US since 2005. The purpose of this report is to provide updated trends in DXA counts, rates, place of service and interpreter specialty for the Medicare fee-for-service population.

METHODS

The 100 % Medicare Physician/Supplier Procedure Summary Limited Data Set between 2005-2019 was used. DXA counts and annual rates per 10,000 Medicare beneficiaries were calculated. Annual distributions of scan performance location, provider type and interpreter specialty were described. Place of service trends (significance assigned at p < 0.05) of the mean annual share of DXA utilization were identified using linear regression.

RESULTS

Annual DXA use per 10,000 beneficiaries peaked in 2008 at 832, declined to 656 in 2015 then increased (p < 0.001) by 38 per year to 807 in 2019. From 2005 to 2019 DXA performance in office settings declined from 70.7 % to 47.2 %. Concurrently, outpatient hospital (OH) DXA increased from 28.6 % to 51.7 %. In 2005, 43.5 % of DXAs were interpreted by radiologists. This increased (p < 0.001) in the office and OH, averaging 0.3 and 2.0 percentage points per year respectively, reaching 73.5 % in 2019. Interpretation by most non-radiologist specialties declined (p < 0.001).

CONCLUSIONS

From 2005-2019, total DXA use among Medicare beneficiaries declined reaching a nadir in 2015 then returned to 2005 levels by 2019. Office DXA declined since 2005 with 51.7 % of all scans now occurring in an OH setting. The proportion of DXAs interpreted by radiologists increased over time, reaching 73.5 % in 2019.

DXA Errors Are Common and Reduced by Use of a Reporting Template

OBJECTIVE

High quality dual energy X-ray absorptiometry (DXA) acquisition, analysis, and reporting demands technical and interpretive excellence. We hypothesized that DXA errors are common and of such magnitude that incorrect clinical decisions might result. In this 2-phase study, we evaluated DXA technical and interpretation error rates in a clinical population and subsequently assessed if implementing an interpretation template reduced errors.

METHODS

In phase 1, DXA scans of 345 osteoporosis clinic referrals were reviewed by International Society for Clinical Densitometry-certified technologists (n = 3) and physicians (n = 3). Technologists applied International Society for Clinical Densitometry performance standards to assess technical quality. Physicians assessed reporting compliance with published guidance, relevance of technical errors and determined overall and major error prevalence. Major errors were defined as "provision of inaccurate information that could potentially lead to incorrect patient care decisions." In phase 2, a DXA reporting template was implemented at 2 clinical DXA sites after which the 3 physicians reviewed 200 images and reports as above. The error prevalence was compared with the 298 patients in phase 1 from these sites.

RESULTS

In phase 1, technical errors were identified in 90% of patients and affected interpretation in 13%. Interpretation errors were present in 80% of patients; 42% were major. The most common major errors were reporting incorrect information on bone mineral density change (70%) and incorrect diagnosis (22%). In phase 2, at these 2 clinical sites, major errors were present in 37% before and 17% after template implementation. Template usage reduced the odds of major error by 66% (odds ratio 0.34, 95% confidence interval 0.21, 0.53, and p < 0.0001).

CONCLUSION

DXA technical and interpretation errors are extremely common and likely adversely affect patient care. Implementing a DXA reporting template reduces major errors and should become common practice. Additional interventions, such as requiring initial and ongoing training and/or certification for technologists and interpreters, are suggested.

CONSENSUS STATEMENT BY THE AMERICAN ASSOCIATION OF CLINICAL ENDOCRINOLOGISTS AND AMERICAN COLLEGE OF ENDOCRINOLOGY ON THE QUALITY OF DXA SCANS AND REPORTS

OBJECTIVE

High-quality dual-energy X-ray absorptiometry (DXA) scans are necessary for accurate diagnosis of osteoporosis and monitoring of therapy; however, DXA scan reports may contain errors that cause confusion about diagnosis and treatment. This American Association of Clinical Endocrinologists/American College of Endocrinology consensus statement was generated to draw attention to many common technical problems affecting DXA report conclusions and provide guidance on how to address them to ensure that patients receive appropriate osteoporosis care.

METHODS

The DXA Writing Committee developed a consensus based on discussion and evaluation of available literature related to osteoporosis and osteodensitometry.

RESULTS

Technical errors may include errors in scan acquisition and/or analysis, leading to incorrect diagnosis and reporting of change over time. Although the International Society for Clinical Densitometry advocates training for technologists and medical interpreters to help eliminate these problems, many lack skill in this technology. Suspicion that reports are wrong arises when clinical history is not compatible with scan interpretation (e.g., dramatic increase/decrease in a short period of time; declines in previously stable bone density after years of treatment), when different scanners are used, or when inconsistent anatomic sites are used for monitoring the response to therapy. Understanding the concept of least significant change will minimize erroneous conclusions about changes in bone density.

CONCLUSION

Clinicians must develop the skills to differentiate technical problems, which confound reports, from real biological changes. We recommend that clinicians review actual scan images and data, instead of relying solely on the impression of the report, to pinpoint errors and accurately interpret DXA scan images.

ABBREVIATIONS

AACE = American Association of Clinical Endocrinologists; BMC = bone mineral content; BMD = bone mineral density; DXA = dual-energy X-ray absorptiometry; ISCD = International Society for Clinical Densitometry; LSC = least significant change; TBS = trabecular bone score; WHO = World Health Organization.

Quality in dual-energy X-ray absorptiometry scans

Dual-energy X-ray absorptiometry (DXA) is the gold standard for measuring bone mineral density (BMD), making the diagnosis of osteoporosis, and for monitoring changes in BMD over time. DXA data are also used in the determination of fracture risk. Procedural steps in DXA scanning can be broken down into scan acquisition, analysis, interpretation, and reporting. Careful attention to quality control pertaining to these procedural steps should theoretically be beneficial in patient management. Inattention to procedural steps and errors that may occur at each step has the possibility of providing information that would inform inappropriate clinical decisions, generating unnecessary healthcare expenses and ultimately causing avoidable harm to patients. This article reviews errors in DXA scanning that affect trueness and precision related to the machine, the patient, and the technologist and reviews articles which document problems with DXA quality in clinical and research settings. An understanding of DXA errors is critical for DXA quality; programs such as certification of DXA technologists and interpreters help in assuring quality bone densitometry. As DXA errors are common, pay for performance requiring DXA technologists and interpreters to be certified and follow quality indicators is indicated.