Risk of damage and mortality in SLE patients fulfilling the ACR or only the SLICC classification criteria. A 10-year, inception cohort study

Objective To compare damage and mortality, from inception up to 10-year follow-up, between SLE patients meeting at baseline the 1997 ACR criteria or only the 2012 SLICC classification criteria. Methods Patients fulfilling the ACR and/or the SLICC classification criteria for SLE were enrolled at inception and followed-up to 10 years at an academic lupus clinic. Damage was defined as SLICC Damage Index (SDI) score 1. We assessed with multivariate Cox models the damage and mortality outcomes, according to SLE classification status at inception, adjusting for potential baseline confounders. Results We recruited 192 patients (69.8% fulfilling at inception the ACR criteria and 30.2% only the SLICC criteria). During follow-up, 24.0% of patients accrued organ damage and 4.2% died. Patients meeting ACR criteria compared to those with SLICC criteria alone presented during follow-up with more cases of lupus nephritis (35.1% versus 13.8%, p<0.01), but less thrombotic antiphospholipid syndrome (4.5% versus 17.2%, p<0.01). The Cox models showed no significant differences in risk for damage [hazard ratio (HR) (95% CI) 0.991 (0.453-2.167)] or death [hazard ratio (HR) (95% CI) 0.694 (0.107-4.506)] between groups. Conclusion The SLE classification status at inception identified different patterns of clinical phenotype, but did not influence damage accrual or mortality up to 10-year follow-up.