DRD2 and obesity due to melanocortin 4 receptor deficiency: In multivariate analysis (accounting for sex, high blood pressure, diabetes, dyslipidemia, chronic alcoholism, smoking, obesity, IVT initiation period, and other treatment acting indirectly on the dopaminergic system), the positive association with older age at first IVT remained significant in patients treated with l-DOPA/DDI (multivariate generalized linear model, P < 0.0001) or DRD2 agonists (multivariate generalized linear model, P < 0.0001).