Background/Purpose: To assess level of agreement between 2002 AECC and 2012 ACR criteria for primary Sjögren’s Syndrome syndrome (pSS) within the Malmö Sjögren’s Syndrome Registry

Methods : The Malmö Sjögren’s Syndrome Registry was established 1984. Patients not fulfilling the AECG criteria were after 2002 designated as having Sicca-Syndrome in contrast to pSS. To date 368 pSS according to AECG and 264 Sicca patients are registered.  Here the ACR-criteria ocular staining score (OSS) ³3 was substituted by van Bijsterveld score ³3. An inter-criteria reliability analysis with Kappa statistic was performed to determine classification consistency.

Results : Of 264 Sicca patients not fulfilling AECG, 81% had sufficient data available to make a decision about fulfilling the ACR criteria. Seven patients (2.7%) fulfilled the ACR critiera but not AECG. All of these fulfilled the ACR criteria due to high titres of ANA and positive RF. None was positive for anti-Ro or La or had a positive salivary gland biopsy. Nor did they have signs of lymphoma risk or had developed lymphoma. Thus, in 97% of the evaluable sicca patients the two criteria sets agreed. Of 368 fulfilling AECG, 268 (73%) had information on all ACR items available, 309 (84%) had sufficient information to evaluate fulfillment of the ACR criteria set. Forty-eight (15%) of AECG positive patients were negative when applying the ACR criteria. 261 of 309 evaluable AECG positive patients were positive according to the ACR criteria, resulting in a consensus in 85%. A calculated kappa-value of 0.781 signals a substantial agreement between the two criteria sets.Amongst the patients not identified by the ACR-criteria there were several with known risk factors for development of lymphoma (table 1). One lymphoma patients (pos biopsy, low C3, high titre ANA but no SSA/SSB or RF, low OSS) was negative in the ACR criteria. Seventeen of the 46 patients not identified by the ACR criteria were previously included in an analysis of germinal center (GC) formation in salivary gland biopsies.  Two of these (12%) were positive for GC. These patients with low complement levels, polyneuropathy, low salivary flow were missed applying the ACR criteria due to lack of severe eye disease and SSA/SSB.

Conclusion : The 2002 AECG and 2012 ACR criteria for SS identify mainly the same patient population (Kappa: 0.781), when applied to the Malmö SS registry containing 386 pSS and 264 sicca syndrome patients. A subgroup of patients lacking SSA/SSB antibodies can be catched only by the ACR criteria. The patients classified as Sjögren’s syndrome by the ACR-criteria in our sicca-cohort had mild disease. On the other hand, several patients with high risk disease manifestations such as hypocomplementemia, GC formation or parotid swelling were missed using the ACR criteria because they lacked severe keratoconjunctivitis sicca. Sensitivity and specificity of the ACR criteria were 85% and 97% respectively.