Depression with immuno-metabolic dysregulation: Testing pragmatic criteria to stratify patients

Introduction: Inflammatory and metabolic processes are linked to depression, but only 25-30% of depressed patients show low-grade inflammation and metabolic dysregulation associated with atypical, energy-related symptoms (AES). Interventions targeting immuno-metabolic dysregulation could benefit depressed patients, but currently no consensus exists how to best select patients with immuno-metabolic dysregulations. Therefore, we investigated which combinations of circulating C-reactive protein (CRP) and AES could identify those depressed individuals with significant immuno-metabolic dysregulation.

Methods: Data are from 1,077 persons with a current Major Depressive Disorder (MDD) of the Netherlands Study of Depression and Anxiety. Immuno-metabolic markers were Interleukin-6 (IL-6), Tumor Necrosis Factor alpha (TNF-α), glycoprotein acetyls, body mass index (BMI), waist circumference, triglycerides, high-density-lipoprotein cholesterol (HDL cholesterol), glucose and leptin. Strata for CRP (≤ 1, < 1 CRP ≤ 3, > 3 mg/L) and AES (score of ≤ 3, 4-5, ≥ 6) were compared on immuno-metabolic markers using analyses of covariance.

Results: Across strata of CRP and AES, there was a dose-response pattern with all higher immuno-metabolic marker levels across higher strata of CRP and AES, with the exception for an association between AES and TNF-α. Persons with both elevated CRP (> 1 mg/L) and high AES (≥ 6) showed a more dysregulated inflammatory and metabolic profile compared to persons with lower CRP and/or AES (p < 0.001).

Conclusion: Our results show a dose-response relationship between both CRP levels and AES with immuno-metabolic risk biomarkers, indicating that CRP and AES combined can capture immuno-metabolic features of MDD. Combining these available and scalable indexes may be an effective strategy to select a patient sample with immuno-metabolic dysregulation who may benefit from treatments targeting inflammatory or metabolic pathways.