Objective: A European League Against Rheumatism (EULAR) SS disease activity index (ESSDAI) and a patient-reported index (ESSPRI) have recently been developed and validated. In our previous study the ESSDAI correlated significantly with serum β2 microglobulin concentration. We now aim to establish whether the ESSPRI is also associated with serum β2 microglobulin or with other patient-reported indices.
Methods: The data on 100 consecutive visits of patients with primary SS (pSS) were reviewed from the patient charts. Patients who had filled out the ESSPRI questionnaire and fulfilled at least four of the revised American-European consensus group criteria for pSS were included. Data were gathered on the ESSPRI (0-10 cm) and on the patient's global health assessment [visual analogue scale (VAS) 0-10 cm] (PGH-VAS), pain-VAS (0-10 cm) and HAQ (range 0-3).
Results: The ESSPRI correlated significantly with the PGH-VAS (r = 0.753, P < 0.0001), pain-VAS (r = 0.656, P < 0.0001) and HAQ (r = 0.542, P < 0.0001) (Spearman's correlation). It also correlated weakly with serum β2 microglobulin (r = 0.214, P = 0.043) and ESR levels (r = 0.235, P = 0.019).
Conclusion: The ESSPRI correlated significantly with other patient-reported indices, serum β2 microglobulin and ESR in patients with pSS. Our results support the view that the ESSPRI is a useful tool in the follow-up of patients with pSS.
Keywords: ESSPRI; activity index; primary Sjögren’s syndrome; serum β2 microglobulin.