Systemic manifestations of primary Sjögren's syndrome out of the ESSDAI classification: prevalence and clinical relevance in a large international, multi-ethnic cohort of patients

OBJECTIVES

To analyse the frequency and characterise the systemic presentation of primary Sjögren's syndrome (SS) out of the ESSDAI classification in a large international, multi-ethnic cohort of patients.

METHODS

The Big Data Sjögren Project Consortium is an international, multicentre registry based on world-wide data-sharing and cooperative merging of pre-existing clinical SS databases from leading centres in clinical research in SS from the five continents. A list of 26 organ-by-organ systemic features not currently included in the ESSDAI classification was defined according to previous studies; these features were retrospectively recorded.

RESULTS

Information about non-ESSDAI features was available in 6331 patients [5,917 female, mean age at diagnosis 52 years, mainly White (86.3%)]. A total of 1641 (26%) patients had at least one of the ESSDAI systemic features. Cardiovascular manifestations were the most frequent organ-specific group of non-ESSDAI features reported in our patients (17% of the total cohort), with Raynaud's phenomenon being reported in 15%. Patients with systemic disease due to non-ESSDAI features had a lower frequency of dry mouth (90.7% vs. 94.1%, p<0.001) and positive minor salivary gland biopsy (86.7% vs. 89%, p=0.033), a higher frequency of anti-Ro/SSA (74.7% vs. 68.7%, p<0.001), anti-La/SSB antibodies (44.5% vs. 40.4%, p=0.004), ANA (82.7% vs. 79.5%, p=0.006), low C3 levels (17.4% vs. 9.7%, p<0.001), low C4 levels (14.4% vs. 9.6%, p<0.001), and positive serum cryoglobulins (8.6% vs. 5.5%, p=0.001). Systemic activity measured by the ESSDAI, clinESSDAI and DAS was higher in patients with systemic disease out of the ESSDAI in comparison with those without these features (p<0.001 for all comparisons).

CONCLUSIONS

More than a quarter of patients with primary SS may have systemic manifestations not currently included in the ESSDAI classification, with a wide variety of cardiovascular, digestive, pulmonary, neurological, ocular, ENT (ear, nose, and throat), cutaneous and urological features that increase the scope of the systemic phenotype of the disease. However, the individual frequency of each of these non-ESSDAI features was very low, except for Raynaud's phenomenon.

Characterization of systemic disease in primary Sjögren's syndrome: EULAR-SS Task Force recommendations for articular, cutaneous, pulmonary and renal involvements

OBJECTIVE

To reach a European consensus on the definition and characterization of the main organ-specific extraglandular manifestations in primary SS.

METHODS

The EULAR-SS Task Force Group steering committee agreed to approach SS-related systemic involvement according to the EULAR SS Disease Activity Index (ESSDAI) classification and proposed the preparation of four separate manuscripts: articular, cutaneous, pulmonary and renal ESSDAI involvement; muscular, peripheral nervous system, CNS and haematological ESSDAI involvement; organs not included in the ESSDAI classification; and lymphoproliferative disease. Currently available evidence was obtained by a systematic literature review focused on SS-related systemic features.

RESULTS

The following information was summarized for articular, cutaneous, pulmonary and renal involvement: a clear, consensual definition of the clinical feature, a brief epidemiological description including an estimate of the prevalence reported in the main clinical series and a brief list of the key clinical and diagnostic features that could help physicians clearly identify these features. Unfortunately we found that the body of evidence relied predominantly on information retrieved from individual cases, and the scientific information provided was heterogeneous. The analysis of types of involvement was biased due to the unbalanced reporting of severe cases over non-severe cases, although the main sources of bias were the heterogeneous definitions of organ involvement (or even the lack of definition in some studies) and the heterogeneous diagnostic approach used in studies to investigate involvment of each organ.

CONCLUSION

The proposals included in this article are a first step to developing an optimal diagnostic approach to systemic involvement in primary SS and may pave the way for further development of evidence-based diagnostic and therapeutic guidelines.