Use of patient age and anti-Ro/La antibody status to determine the probability of patients with systemic lupus erythematosus and sicca symptoms fulfilling criteria for secondary Sjogren's syndrome

Sir, The development of internationally agreed diagnostic/classification criteria for the diagnosis of both primary and secondary Sjögren's syndrome (SS) has been a major advance for clinical research into this condition [1, 2], enabling clinical therapeutic trials and other studies to generate widely generalizable and accepted results. The presence of antibodies directed against Ro and/or La antigens (Ro/La) is required in order to fulfil these criteria in patients with primary SS who have not had a labial gland biopsy performed or in whom this did not yield a diagnostic result [2]. The criteria for secondary SS include subjective dry eye and/or dry mouth symptoms and two of the following: objective evidence of reduced tear formation; objective evidence of reduced salivary flow rate; and a positive labial gland biopsy [1]. Anti‐Ro/La antibodies have not, however, been included in the criteria for secondary SS as they have not shown significant results using univariate analysis [1]. It is well established that the prevalence of SS among rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) patients increases with patient age [3], but this also does not form part of the classification criteria.