809. Atypical Symptoms Associated with Metabolic, But Not Inflammatory, Biomarkers in Bariatric Surgery Patients with Depression

Abstract

Abstract Background Obesity and depression are highly prevalent conditions significantly impacting global health; in England alone, 25% of adults are reported to have obesity and 20% depression. With this, the high comorbidity is unsurprising, contributing to a vicious cycle between the two conditions. In parallel, there has been a growing interest in the role of immune and metabolic abnormalities within and on this comorbidity. While traditional models have focused on more typical symptoms of depression, recent research highlights the relevance of understanding atypical symptoms (e.g., hypersomnia, weight gain, increased appetite, and lethargy). Aims & Objectives We aimed to investigate 1) changes in typical and atypical depression symptoms before and 3-years after bariatric surgery and 2) which metabolic and inflammatory biomarkers are associated with these changes. Method We investigated participants from the bariatric surgery and depression (BARDEP) study for whom both pre-surgery (age=46.7±11.6; BMI=48.5±6.6kg/m2) and 3-year post-surgery (age=49.7±11.3; BMI=36.6±7.0kg/m2) data were obtained. All participants had obesity (BMI ≥30kg/m2), with (n=15) and without (n=22) comorbid baseline depression. Symptoms were measured using the Structured Interview Guide for the Hamilton Depression Rating Scale with Atypical Depression Supplement (SIGH-ADS) and divided into three clusters: HAM-D-17, Atypical-8, and total scores. Blood samples were collected to measure peripheral inflammation in serum. Weight-loss percentage (WLP) and BMI were calculated. Group differences (t-tests/Wilcoxon), Spearman’s correlations, and regression analyses were computed. Results In MDD, total SIGH-ADS scores were significantly reduced post-surgery [t(13)=1.974, p=0.035, one-tailed], seemingly driven by distinct improvement in atypical symptoms of depression [t(13)=1.939, p=0.037, one-tailed] while HAM-D (or typical) scores did not change. Nevertheless, MDD participants remained significantly more likely to report worse symptoms than controls in all three domains at 3-years. In contrast, controls saw significant worsening in typical [t(21)=2.383, p=0.013], atypical [t(21)=2.996, p=0.003], and total scores [t(21)=3.172, p=0.002], though remained below the relevant clinical thresholds for all domains. Both MDD and control groups saw significant (all p<0.001) reductions in weight [t(14)=5.083 and t(21)=14.34 respectively], BMI score [t(14)=9.449; t(21)=14.37], and trunk muscle mass [t(12)=4.993; t(18)=6.385] by 3-years. In MDD, only IL-6 (Z=-3.059; p=0.002), and TNF-α (Z=-3.059; p=0.002) were significantly decreased by 3-years, with neither correlated with atypical symptoms changes (Δ). Atypical symptom improvement was correlated with WLP [r(13)=-0.589, p=0.021], Δ-weight [r(13)=0.697,p=0.004], Δ-BMI [r(13)=0.556, p=0.031], and Δ-fat mass [r(9)=0.700, p=0.016]. Discussion & Conclusions Our data suggests a unique relationship between atypical symptoms and metabolic (i.e., WLP, BMI, fat/muscle), but not inflammatory, biomarkers. Our findings suggest weight-loss interventions may be particularly beneficial in the long-term for those individuals with atypical depression.