PTPN1 and type 2 diabetes mellitus: The first model, which included biologically associated variables (history of T2DM and metformin use), found that PTP-1B expression remained significantly associated with the presence of APFs (Odds Ratio [OR] 1.21, 95% Confidence Interval [CI] 1.01-1.45, p=0.037), independent of prior T2DM diagnosis or metformin use.