Body Composition and Body Mass Index Show Comparable Associations with Adalimumab Exposure and Immunogenicity in Noninfectious Uveitis

Purpose: To evaluate whether bioimpedance-derived body composition parameters are associated with adalimumab exposure and immunogenicity in noninfectious uveitis (NIU) and whether they provide information complementary to body mass index (BMI). Methods: Forty-five patients with NIU receiving adalimumab monotherapy (40 mg every 2 weeks) for at least 12 months were enrolled in this single-center cross-sectional study. Body composition was assessed by use of multifrequency bioimpedance analysis (InBody 770). Serum adalimumab trough concentrations and anti-adalimumab antibodies (AAA) were measured. Associations were evaluated using Pearson correlations, multivariable linear regression, and receiver operating characteristic (ROC) analyses. Results: Adalimumab trough concentrations were moderately inversely correlated with BMI ( r = −0.51, P = 0.0004), body fat mass ( r = −0.51, P = 0.0004), percent body fat ( r = −0.48, P = 0.001), and visceral fat area ( r = −0.53, P = 0.0002), but not with lean-mass parameters. In separate multivariable models adjusted for age and sex, each adiposity measure was independently associated with trough concentrations (adjusted R 2 0.18–0.25). ROC analysis showed comparable discrimination of low drug exposure for BMI (area under the curve [AUC] 0.69) and body composition metrics (AUC 0.70–0.74; DeLong P > 0.5). BMI showed the strongest correlation with AAA levels ( r = 0.58, P < 0.0001). Conclusions: Bioimpedance-derived adiposity measures and BMI showed similar associations with adalimumab exposure in NIU. Body composition may offer complementary biological context for interpreting pharmacokinetic variability and immunogenicity. Future studies are warranted to determine whether body composition data improve therapeutic drug monitoring in uveitis.