A multivariate regression revealed IL-6 independently predicted lower UPDRS III scores (β = −0.497, p = 0.018), TNF-α correlated with PD duration (β = 0.689, p < 0.001) and IL-1β correlated with PDQ-39 scores (β = 0.462, p = 0.002) in patients with PD–T2DM. This evidence concerns the gene IL6 and Parkinson disease.