Validity of systemic lupus erythematosus disease activity score (SLE-DAS) for definition of lupus low disease activity state (LLDAS).

INTRODUCTION

SLE disease activity score (SLE-DAS) is a novel, rapid, continuous and comprehensive score that overcomes the drawbacks of SLEDAI-2 K. Low lupus disease activity state (LLDAS) has been targeted as an endpoint in many clinical trials and as a favourable outcome in clinical practice. Therefore, our objective in the current study is to evaluate the validity of SLE-DAS for defining LLDAS as an objective in the treat-to-target strategy.

METHODS

A cross-sectional study was carried out on 117 SLE patients who were diagnosed according to Systemic Lupus International Collaborating Clinics (SLICC) classification criteria for SLE. Patients were evaluated for disease activity by both SLEDAI-2 K and SLE-DAS. Additionally, patients were divided according to the SLEDAI-2 K-derived LLDAS definition into two groups: low disease activity (LDA) group and high disease activity (HDA) group. The validity of SLE-DAS for the definition of LLDAS was evaluated in comparison to SLEDAI-2 K.

RESULTS

SLE-DAS shows highly significant positive correlation (r = 0.743, p < 0.001) with SLEDAI-2 K. The ROC curve revealed that SLE-DAS is valid for the assessment of activity with the best detection of LLDAS was at 6.62 with 95.5% sensitivity, 79.3% specificity and 89.6% accuracy. Moreover, it had a good agreement with the SLEDAI-2 K-derived definition of LLDAS (k = 0.765, p < 0.001).

CONCLUSION

SLE-DAS is a valid score for the definition of LLDAS which can be used in the clinical practice as a simple and precise standalone criterion. Key Points • Correlation between SLEDAI-2K and SLE-DAS revealed a high significance. • Identify SLE-DAS cut-off 6.62 for the definition of LLDAS. • There is a good agreement between SLEDAI-2K-derived definition of LLDAS and SLE-DAS definition.