Measuring Choroid Thickness as a Marker of Systemic Inflammation in Patients With Ankylosing Spondylitis.

BACKGROUND AND OBJECTIVE: Ankylosing spondylitis (AS) is an inflammatory disease, and choroidal thickness (CT) has been proposed and evaluated as a potential marker of systemic inflammation associated with AS and other inflammatory diseases. This study compared CT measurements taken from patients with severe AS disease activity without eye inflammation with those taken from healthy subjects. METHODS: This cross-sectional, multicenter study compared CT in 44 patients with high AS disease activity, and no history of eye inflammation with CT in 44 matched healthy subjects aged between 18 and 65 years. In the AS group, the correlation between CT and C-reactive protein, human leukocyte antigen (HLA) B27 positivity, disease duration, and disease activity was calculated. RESULTS: Mean CT values of patients with AS were significantly higher in the right eye, the left eye, and the thickest choroid eye. The right eye mean CT was 338.3 ± 82.8 µm among patients with AS and 290.5 ± 71.2 µm among healthy subjects (p = 0.005). The left eye mean CT was 339.5 ± 84.7 µm for patients with AS and 298.4 ± 68.9 µm for healthy subjects (P = 0.015). The thickest choroid eye CT was 358.4 ± 82.1 µm among patients with AS and 314.1 ± 65.2 µm among healthy subjects (P = 0.006). We did not find a significant correlation between CT and disease activity, C-reactive protein, human leukocyte antigen B27 positivity, or disease duration. CONCLUSIONS: Patients with active AS but without a history of eye inflammation had a thicker choroid than healthy subjects. This finding suggests that CT is a marker of systemic inflammation in patients with inflammatory disease, regardless of known eye symptoms.

Choroidal Thickness Is a Biomarker Associated With Response to Treatment in Ankylosing Spondylitis.

OBJECTIVE: Choroidal thickness (CT) has been evaluated as a marker of systemic inflammation in ankylosing spondylitis (AS). This study evaluates the CT of AS patients before and after 6 months of biological treatment. METHODS: This longitudinal multicenter study evaluated CT in 44 AS patients. The correlations between CT and C-reactive protein (CRP) with disease activity indices were calculated. The concordance between CT and CRP was determined. We assessed factors associated with response to treatment. Clinically important improvement was defined as a decrease in Ankylosing Spondylitis Disease Activity Score of 1.1 points or greater. RESULTS: Forty-four eyes in patients aged 18 to 65 years were included. Mean CT values were significantly higher at baseline than after 6 months of treatment (baseline: 355.28 ± 80.46 µm; 6 months: 341.26 ± 81.06 µm; p < 0.001). There was a 95% concordance between CT and CRP at baseline and 6 months. Clinically important improvement was associated with lower baseline CT and age as independent factors (odds ratios, 0.97 [95% confidence interval, 0.91-0.93; p = 0.009] and 0.81 [95% confidence interval, 0.7-0.95; p = 0.005]), with baseline CT of less than 374 µm (sensitivity 78%, specificity 78%, area under the curve 0.70, likelihood ratio 3.6). CONCLUSIONS: Choroidal thickness decreased significantly after 6 months of biological treatment in all treatment groups. Choroidal thickness and CRP had a 95% concordance. A high CT was associated with a risk of biological treatment failure. Choroidal thickness can be considered a useful biomarker of inflammation and a factor associated with response to treatment in AS.