KLK3 and obesity due to melanocortin 4 receptor deficiency: Given that metformin use may be confounded by the metabolic status, a multivariable regression analysis was performed with adjustment for PSA, T stage, Gleason score, and obesity (BMI ≥ 30), and metformin use remained significantly associated with worse PFS (aHR: 2.30, 95% CI: 1.01–5.22) (Table 7).