Associations Between Major Depressive Disorder, Multimorbidity Burden, and Inflammatory Biomarkers (NLR, PLR, MLR, SII, and MHR) in a Primary Care Population.

In this large real-world primary care cohort, major depressive disorder was common and strongly linked to multimorbidity.

Although platelet-to-lymphocyte ratio and MHR differed significantly between groups, they were not independently associated with major depressive disorder after adjustment, suggesting that these differences may be driven by multimorbidity and related clinical factors rather than independent disease-specific effects.