Item-specific factors associated with damage accrual in systemic lupus erythematosus : insights from a multiethnic, multinational Latin American cohort

Abstract

Objective To identify factors associated with individual Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index (SDI) accrual items in 1385 patients from the Latin American SLE incident cohort (GLADEL (Grupo Latino Americano Del Estudio de Lupus)). Methods Longitudinal cohort study. SDI assessed yearly, and damage accrual defined as a SDI change in any individual item during follow-up. Sociodemographic and clinical characteristics at entry, along with regular medication use up to the month prior to each damage item accrued, were analysed using multivariate Cox proportional hazard models with time-varying hazard risk effect performed. Models for overall damage and 10 items with at least 28 patients per item are reported. Results New damage was accrued by 658 patients with SLE (48%) over a median of 54 months (p25-75: 29-71) of follow-up. Mestizo ethnicity, recent SLE Disease Activity Index (SLEDAI) and immunosuppressants were predictors of overall damage accrual, while antimalarials and rural residence were protectors; mixed effects were observed for SDI >0 and glucocorticoids (GCs) use. Protectors for scarring chronic alopecia (23.7% at 7 years follow-up) included older age, longer disease duration, diagnostic delay, SDI >0 and cytotoxic use. Proteinuria >3.5 g/24 hours (11.5% at 7 years follow-up) was associated with protective factors like older age, longer disease duration and higher GCs dose, while risk factors were Mestizo ethnicity, low medical coverage, higher SLEDAI scores and cytotoxic use. In addition, Mestizo ethnicity was a risk factor for estimated glomerular filtration rate <50% and end-stage renal disease (ESRD) whereas antimalarial protected from ESRD. GCs were risk factors for pericarditis, retinal change or optic atrophy but provided protection against proteinuria >3.5 g/24 hours. Recent disease activity and cytotoxic use were significant risk factors for additional items. Conclusions Factors associated with damage accrual differ substantially by individual SDI items. Mestizo ethnicity and recent disease activity increased renal risks, while antimalarials were protective. GCs showed mixed effects. Item-specific strategies are crucial to mitigate long-term damage.