Risk factors of damage in early diagnosed systemic lupus erythematosus: results of the Italian multicentre Early Lupus Project inception cohort

Abstract

Objective: To investigate risk factors for damage development in a prospective inception cohort of early diagnosed SLE patients.

Methods: The Early Lupus Project recruited an inception cohort of patients within 12 months of SLE classification (1997 ACR criteria). At enrolment and every 6 months thereafter, the SLICC/ACR Damage Index was recorded. The contribution of baseline and time-varying covariates to the development of damage, defined as any SLICC/ACR Damage Index increase from 0 to ≥1, was assessed using univariate analysis. Forward-backward Cox regression models were fitted with covariates with P < 0.05 to identify factors independently associated with the risk of damage development.

Results: Overall, 230 patients with a mean (s.d.) age of 36.5 (14.4) years were eligible for this study; the mean number of visits per patient was 5.3 (2.7). There were 51 (22.2%) patients with SLICC/ACR Damage Index ≥1 after 12 months, 59 (25.6%) after 24 months and 67 (29.1%) after 36 months. Dyslipidaemia [P = 0.001; hazard ratio (HR) 2.9; 95% CI 1.5, 5.6], older age (P = 0.001; HR 3.0; 95% CI 1.6, 5.5), number of organs/systems involved (P = 0.002; HR 1.4; 95% CI 1.1, 1.8) and cardiorespiratory involvement (P = 0.041; HR 1.9; 95% CI 1.0, 3.7) were independently associated with an increased risk of developing damage. Risk profiles for damage development differed for glucocorticoid-related and -unrelated damage. HCQ use (P = 0.005; HR 0.4; 95% CI 0.2, 0.8) reduced the risk of glucocorticoid-unrelated damage.

Conclusion: We identified risk factors of damage development, but little effect of glucocorticoids, in this early SLE cohort. Addressing modifiable risk factors from the time of SLE diagnosis might improve patient outcomes.

Keywords: BILAG; HCQ; SLE; SLICC/ACR Damage Index; dyslipidaemia; early diagnosis; glucocorticoids; organ damage.