In participants taking venlafaxine (SNRI), we found that, amongst people with diabetes, poor metabolizers for CYP2D6 had higher HbA1c than normal metabolizers (mean difference: 10.15mmol/mol; 95% CI (2.63,17.67); p = 0.008) (see Table 5 and Table 6, Figure 2, and Supplementary Table S12). The gene discussed is CYP2D6; the disease is diabetes mellitus.