To investigate longitudinal changes of the EULAR SS Patient-Reported Index (ESSPRI) and EULAR SS Disease Activity Index (ESSDAI), and identify factors associated with patient acceptable symptom state (PASS) in patients with primary SS (pSS).
We assessed ESSPRI, ESSDAI, clinical ESSDAI (ClinESSDAI), EULAR Sicca Score, EuroQoL 5-dimension (EQ-5D), Fatigue Severity Score, Beck Depression Inventory, and patient global assessment (PGA) for pSS, and visual analogue scale (VAS) scores for glandular and extra-glandular symptoms at baseline and follow-up. The responses to the currently available standards of care were evaluated by the PASS, the minimal clinically important improvement (MCII) of ESSPRI and ESSDAI, and a modified SS Responder Index-30 (mSSRI-30) response.
Among 115 patients enrolled, 102 (88.7%) completed a median 3-year follow-up. The ESSPRI, ClinESSDAI and EQ-5D levels remained stable, although the PGA and ESSDAI significantly improved (both P <0.05). Of the 102 patients, 52 (51.0%) patients achieved the PASS at the follow-up and tended to attain the ESSPRI-MCII and mSSRI-30 (both P < 0.001) more frequently than the non-PASS group. Multivariate analysis revealed that the PASS was significantly associated with baseline ESSPRI negatively [odds ratio (OR) 0.609] and ESSDAI positively (OR 1.224). When categorized using baseline ESSPRI and ESSDAI, a subgroup of low ESSPRI and high ESSDAI reached a PASS achievement rate of 79.3%.
Although longitudinal changes in ESSPRI and ClinESSDAI are stable in pSS, baseline ESSPRI and ESSDAI could provide prognostic information on the subsequent achievement of PASS, using currently available treatments. A categorization model using ESSPRI and ESSDAI may have clinical implications.