Objective: To determine the association between disease activity and choroidal thickness in patients with systemic lupus erythematosus (SLE). Methods: We conducted a cohort study of 24 SLE patients and 13 healthy controls recruited at Washington University School of Medicine between June 2019 and November 2021. SLE disease activity was assessed using the SLE Disease Activity Index-2000 Responder Index-50 (S2K RI-50). Patients were divided into four groups: high disease activity/no lupus nephritis (HDA/no LN; S2K RI-50 > 4), HDA/active LN (HDA/active LN; S2K RI-50 > 4), low disease activity/inactive LN (LDA/inactive LN; S2K RI-50 <= 4), and LDA/no LN (LDA/no LN; S2K RI-50 <= 4). LDA/no LN patients were age-, sex-, and race-matched to healthy controls and patients in other SLE groups. Choroidal thickness of the right eye was measured blinded to disease activity on a horizontal section through the fovea on optical coherence tomography images taken within a week of disease assessment. Results: Patients with HDA had choroidal thickening compared with matched patients with LDA. After controlling for multiplicity, choroidal thinning remained statistically significant at 1000 mu m nasal to the fovea (308 +/- 68 vs 228 +/- 64 mu m, p = 0.001). Choroidal thickness was not different between LDA/no LN and LDA/inactive LN or healthy controls. Conclusion: HDA in patient with SLE is associated with increased choroidal thickness whereas comorbid inactive LN did not affect choroidal thickness. Additional studies in a larger longitudinal cohort are needed to study whether choroidal thickness may be used as a noninvasive, adjunctive measure for disease activity in SLE.
