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CLASSIFICATION CRITERIA

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Sjogren's classification criteria are a research tool. They are not meant to be used as diagnostic criteria in the routine clinic setting. 

  • Classification criteria are not diagnostic criteria. 

  • There are no diagnostic criteria for Sjogren's (77).

  • People who fulfill the Sjogren's classification criteria almost certainly have Sjogren's. 
    However, "Many patients also do not fulfill the classification criteria that are very stringent and meant only for use in clinical trials."~ The Sjogren's Foundation
     

Classification criteria are often misused as diagnostic criteria. 

Sjogren's is a complex disease. Sjogren's is a clinical diagnosis that considers many factors, including history, physical examination, laboratory findings, and more. Diagnosis should never be reduced to a box-ticking exercise of the classification criteria. 

If you think you might have Sjogren's but do not meet the classification criteria, see  MYTHS ABOUT DIAGNOSIS and Why is it so hard to get diagnosed? for self-advocacy tools. 
 

Sjogren's classification criteria serve two main purposes.

1.They are used to standardize research populations. In other words, they are necessarily strict to ensure that everyone enrolled in a study fits the same picture of Sjogren's. 

2. They help distinguish similar diseases from each other.

Classification criteria should never substitute for clinical judgment when diagnosing Sjogren's.

Because they are strict, people who meet the classification criteria are highly likely to have Sjogren's. However, a significant number with Sjogren's will not meet the classification criteria.

Rheumatologists may be unaware of the limited accuracy of tests and that the over-emphasis on sicca features distorts the classification criteria.(3677).  The classification criteria need to be updated because they do not reflect the multisystem nature of Sjogren's disease. Requiring patients fulfill the classification criteria to be diagnosed with Sjogren's leaves many people who do have the disease undiagnosed (36139). It may take years of progression before they meet these criteria. Some people with Sjogren's may never meet the classification criteria. 
 

2016 Sjogren's Classification Criteria

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Total Score  ≥ 4  to Classify as Primary Sjogren’s. For detailed exclusions and inclusions, see Criswell, Shiboski, et al. (4)

Limitations of the 2016 Classification Criteria (CC)

  1. Sjogren’s is a systemic disease with widespread manifestations. The CC are heavily weighted toward sicca, reinforcing the misconception that Sjogren’s is mostly a dryness disease. The CC do not take into account history and physical examination, which often provide important clues to diagnosis. The 2016 criteria are the best we have to date. When interpreting research studies, it is important to keep in mind that they (necessarily) select for a subset of Sjogren’s patients that do not represent all Sjogren's patients.
     

  2. Sicca (dryness) symptoms may occur without objective measurements of dryness. On the other hand, some patients with measurable dryness do  not report feeling dry. Changes in the composition of secretions, inflammation of the salivary and lacrimal glands, and neuropathic pain all contribute to sicca symptoms. These factors are not considered in the CC sicca measurements, which only measure the volume of secretions.
     

  3. About 20% (1 in 5) of patients initially present with no obvious sicca manifestations. This is sometimes referred to as “occult Sjogren’s.” Patients in this group often do not meet the classification criteria (3).
     

  4. The classic Sjogren’s antibody, SSA, is the only test unrelated to glandular damage in the 2016 criteria. Yet SSA is absent in 30 % - 40% of Sjogren’s patients, possibly more (5, 6,7).


Complicating matters further, SSA can be positive in other autoimmune diseases and in healthy people (6). Better biomarkers are needed that will enable early and accurate Sjogren's diagnosis.
 

The Minor Salivary Gland Biopsy (MSGB), aka "lip biopsy" is the only way to “confirm” a Sjogren's diagnosis in SSA-negative patients. Yet this test is not always available and requires specialized training for both the procedure and the interpretation of the sample (pathology). Even in ideal circumstances, the MSGB is only positive about 80% of the time.   

Limitations of CC

Each test on the classification criteria has limitations.

  • See comments about SSA (anti-Ro) and the minor salivary gland biopsy (lip biopsy)above, and MYTHS ABOUT DIAGNOSIS. 
     

  • Unstimulated salivary flow testing is not routinely available in most clinic settings.
     

  • Both the Schirmer’s test and the unstimulated salivary flow test measure the volume of secretions at a single point in time, as opposed to the amount of tears and saliva produced throughout the day. Patients are typically driest in the evening, not during clinic hours. The amount of secretions may not reflect the severity of sicca. These tests tell you nothing about alterations of the composition of saliva and tears, or the inflammation of the eyes and oral cavity, which are part of Sjogren's sicca.  
     

  • Many patients cannot tolerate abstaining from artificial tears prior to their clinic appointment. Recent instillation of these or other eye drops invalidates the Schirmer’s test.
     

  • The ocular staining score (OSS) measures corneal damage. Milder corneal erosions may heal with newer treatments such as autologous serum eye drops and scleral lenses. Sometimes the cornea heals enough to produce a normal OSS on follow-up, despite an initial positive result. This does not mean that Sjogren's went into remission! 

The REAL WORLD IMPACT – What happens when classification criteria are used exclusively for diagnosis?

Seronegative patients (usually meaning SSA-negative) tend to have especially long delays to diagnosis, or may never be diagnosed.
 

People who present with an incomplete clinical picture often remain undiagnosed an untreated for decades before a Sjogren’s is suspected. Sjogren’s often develops slowly. Incomplete presentations are common early in the disease. Sicca may lag behind other manifestations. 

Sjogren’s may not be recognized in cases of early organ system or neurological involvement. Many of these patients have no obvious sicca manifestations early on. They are often misdiagnosed with rheumatoid arthritis or systemic lupus erythematosus because clinicians often assume, incorrectly, that Sjogren’s does not cause systemic disease. 

Early organ system manifestations are associated with poorer prognosis. For these patients, the stakes are very high. They need Sjogren’s-specific care as early as possible
(3, 23, 36).

My own long journey to diagnosis, described in 12 Reasons People with Sjogren's Don't Get Diagnosed, illustrates why classification criteria should not substitute for clinical judgment.  

Sjogren's is a clinical diagnosis that is supported by, but not ruled out by,  diagnostic tests. 

Updated 04-16-2024

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