Nonradiographic Axial Spondyloarthritis Receives New Diagnostic Code

International Classification of Diseases and Related Health Problem 10th Revision, ICD10
International Classification of Diseases and Related Health Problem 10th Revision
Rheumatologist Jeff Stark, MD, discusses the diagnostic code developed specifically for nonradiographic axial spondyloarthritis.

For the rheumatology community and patients with nonradiographic axial spondyloarthritis (nr-axSpA), several recent developments are expected to lead to significant improvements in diagnosis and treatment of the disease. In addition to the approval of 2 new therapies indicated for nr-axSpA in June 2020 by the United States Food and Drug Administration (FDA), an upcoming revision of the International Statistical Classification of Diseases, Tenth Revision (ICD-10) will debut diagnostic coding options for this disease.1,2

While advances in MRI have enabled the detection of nr-axSpA in clinical practice, the lack of a diagnostic code has hindered widespread recognition of the disease in the healthcare community.3 As a result, patients often experience protracted diagnostic and treatment delays along with a sense of invalidation of their condition. This gap has also impacted epidemiologic research in the area, which increasingly relies on the use of administrative healthcare data.4

The introduction of the new diagnostic coding options represents an important step toward improving the study and management of nr-axSpA.

We spoke with rheumatologist Jeff Stark, MD, head of United States Medical Immunology at UCB, to discuss the significance and clinical implications of this long-awaited update for nr-axSpA.  

What is the significance of the new diagnostic code for nr-axSpA and why was this change needed for clinical practices?

Clinical and scientific advances in medicine can outpace the administrative systems that support healthcare day-to-day. For more than a decade, diagnostic tools and published criteria have enabled physicians to identify patients with nr-axSpA. However, in the absence of diagnostic coding, healthcare providers struggled to capture an accurate diagnosis in administrative databases, such as electronic health record (EHR) systems, which intrinsically rely on ICD-10 codes to characterize patients with the disease. This shortcoming meant that healthcare professionals were forced to use less accurate or specific options in the ICD-10 coding manual.

The absence of approved codes for nr-axSpA has limited awareness and recognition of the condition. Moreover, inconsistent coding limits the ability to study these patients in real-world databases and to generate data on their clinical journey. Perhaps, most importantly, the absence of specific diagnostic coding has disempowered patients, many of whom already experience a circuitous diagnostic process, by making them feel their disease is somehow less “real.”

How did this update come about, and what can we learn from this in terms of other conditions in rheumatology that warrant specific diagnostic codes?

While the entire coding system is updated periodically, these updates occur infrequently and may be separated by several years. For this reason, the modification of the existing ICD-10 coding manual allows for a more timely revision to reflect current clinical knowledge and needs. In the US, this revision process is overseen by the ICD-10 Coordination and Maintenance Committee, a subcommittee of the Centers for Disease Control and Prevention (CDC).

Two years ago, in collaboration with several US professional rheumatology organizations and patient advocacy groups, UCB brought this issue to the committee for its consideration. After thoughtful deliberation, the committee has announced that nr-axSpA will be officially indexed to ICD-10 subcategory M46.8 and corresponding diagnostic codes will become effective October 1, 2020.

Modification of the coding manual is a thoughtful and deliberate process, and proposed revisions must meet a high bar of clinical validity and necessity to be considered. In this instance, the consistent voice of diverse stakeholders in the patient and professional community helped demonstrate the need for specific codes.

What should clinicians know about using the new coding options in diagnosing nr-axSpA?

While the M46.8 subcategory exists and can be used today, as of October 1, 2020, specific codes in the M46.8 subcategory will be recognized formally as the appropriate coding option for nr-axSpA. Shortly after this date, clinicians in the US should be able to search for nr-axSpA within their EHR/electronic medical record systems and select an appropriate code of their choice within the M46.8 subcategory. 

In addition to this important development, what are some other pressing needs pertaining to nr-axSpA?

While nr-axSpA is well-known to most rheumatologists, many of these patients may be seeing healthcare professionals in other specialties who may be less familiar with the disease. This broad dispersal of patients across the healthcare landscape is likely for the delay in diagnosis (between 5-8 years) experienced by the typical patients with nr-axSpA.5 

Wider education on nr-axSpA remains a need, especially in areas like epidemiology, gender patterns, extraspinal manifestations, and effective treatment. However, these approved and specific coding options in the M46.8 subcategory will help to encourage greater awareness of these patients by not only rheumatologists, but the healthcare community as a whole. This step forward will give patients the confidence that their disease is recognized and acknowledged by the healthcare community.


  1. Spondylitis Association of America. Not one, but two new medications approved this month for non- radiographic axial spondyloarthritis (nr-axSpA). Accessed July 21, 2020.
  2. UCB. UCB statement on non-radiographic axial spondyloarthritis diagnostic code update. News release. Published July 22, 2020. Accessed July 31, 2020.
  3. Robinson PC, Sengupta R, Siebert S. Non-radiographic axial spondyloarthritis (nr-axSpA): advances in classification, imaging and therapy. Rheumatol Ther. 2019;6(2):165-177
  4. Wang R, Ward MM. Epidemiology of axial spondyloarthritis: an update. Curr Opin Rheumatol. 2018;30(2):137-143.
  5. Lubrano E, De Socio A, Perrotta FM. Unmet needs in axial spondyloarthritis. Clin Rev Allergy Immunol. 2018;55(3):332-339.