Classification criteria for Sjogren's syndrome: a critical review

Over the years, several different criteria sets have been proposed for the classification of Sjögren's syndrome (SS), but none of them has been widely adopted by the scientific community until the publication of the 1993 Preliminary European Classification criteria. These Classification criteria have been largely employed both in clinical practice and in observational and interventional studies for many years. In 2002 the Preliminary European Criteria were re-examined by a joint American and European Committee. The result of this revision were the American and European Consensus Group classification criteria (AECG-criteria) which introduced more clearly defined rules for classifying patients with primary or secondary SS, and provided more precise exclusion criteria. These AECG-criteria set is now considered to be valid to ensure a specific diagnosis of SS by the vast majority of the expert in the field. To date, the AECG-criteria have been cited more than 1.304 in literature and have been used to estimate the point prevalence of the disease in several studies conducted in Greece, UK, Turkey and Norway. However, when employed in epidemiologic studies or in daily practice, the AECG-criteria have demonstrated a higher specificity (75%), but a lesser sensitivity (65.7%) in comparison to the previous Preliminary European criteria, indicating an average prevalence of pSS at ~ 0.2% in the adult population, which is far lower than previously reported. In this paper we will critically analyse the "pro and cons" of the current AECG-criteria and of the potential usefulness of some potential revisions.