Background/Purpose: SLE is an autoimmune disease with widespread organ involvement. High disease activity has previously been associated with higher risk of organ damage and mortality. However, it is often difficult to resolve which clinical symptoms reflect SLE disease activity, leading to potential over or under treatment. Inflammation of the choroid (the outer vascular layer of the eye) may reflect inflammation of the kidney in lupus, since both have similar vascular designs, contain fenestrated capillaries, are composed of a3-5 type IV collagen, and are organized in lobules. In addition, clinical choroidopathy has been observed in patients with SLE high disease activity, especially renal or CNS involvement. In a recent publication, choroid thickening (CT) was reported in a cohort of SLE patients compared to non-SLE controls, but disease activity was not described. In the present study, we investigated whether CT is associated with extra-renal SLE flare, extra-renal disease activity, or renal disease in complete remission. We hypothesize that CT is associated with SLE disease activity.

Methods: This is a retrospective case-control study of SLE patients meeting either American College of Rheumatology (ACR) or Systemic Lupus International Collaborating Clinics criteria who were followed at Washington University School of Medicine Rheumatology, Nephrology, or Ophthalmology clinics. Data was derived from 21 patients with SLE, 14 of whom had biopsy-proven lupus nephritis (LN). The nephritis of all LN patients was in complete clinical remission as defined by the ACR. Disease activity was assessed using the S2K RI-50 instrument, with scores > 4 defined as active. Major flare was defined by Fortin criteria. CT was measured at three locations through the fovea using optical coherence tomography, a noninvasive imaging modality used by ophthalmologists to follow retinal disease. After exporting images into Adobe Photoshop, CT was measured independently by 2 investigators. Intra-rater and inter-rater reliabilities were 0.982 and 0.96, respectively. Comparisons were made with Student’s t-test for parametric and Mann-Whitney U for nonparametric data.

Results: Compared to control subjects with inactive SLE and no history of LN, the CT of subjects with active SLE was marginally thicker (348 µm [IQR 308-425] vs 264 [IQR 228-343], p = 0.061 at 500 µm nasal to the fovea, n = 4 vs 14 eyes, respectively). However, the CT of subjects who met criteria for extra-renal flare (293±87µm vs 270±74µm, p = 0.286 at 500 µm nasal to the fovea, 310±89µm vs 284±74 µm, p = 0.229 at the fovea, and 301±84µm vs 274±68µm, p = 0.163 at 500 µm temporal to the fovea, n = 21 vs 41 eyes) or inactive LN were not different from controls (272±79 µm vs 268±69 µm, p = 0.862 at 500 µm nasal to the fovea, 281±78 µm vs 288±70 µm at the fovea, and 271±64µm vs 272±72µm at 500 µm temporal to the fovea, n = 23 vs 20 eyes).

Conclusion: CT may be associated with some manifestations of active SLE (S2K RI-50 > 4). CT was not associated with extra-renal flare or LN in remission. Study conclusions are limited by the retrospective observational design and small sample size.  The study supports the need for additional research examining CT – SLE disease activity relationships.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/sle-disease-activity-may-be-associated-with-choroidal-thickness/