Constructing and validating a frailty index as a novel health measure in systemic lupus erythematosus

Abstract

For patients with systemic lupus erythematosus (SLE), clinical outcomes are highly variable and challenging to predict. Such differences in susceptibility to adverse health outcomes can be quantified using a frailty index (FI). We used data from an international cohort of recently-diagnosed SLE patients to construct and validate the first FI for patients with SLE, to be known as the SLICC-FI. We assessed whether the SLICC-FI was predictive of future adverse health outcomes including hospitalizations, organ damage and mortality, after adjustment for the SLICC/ACR Damage Index (SDI), a known prognostic factor in SLE. Higher baseline SLICC-FI scores were associated with more hospitalizations, increased organ damage accrual, and increased mortality risk during follow-up. For all three outcomes, the SLICC-FI improved prediction when compared to the SDI alone. The SLICC-FI holds potential value in quantifying vulnerability among patients with SLE and provides additional prognostic information when compared to existing SLE measures.