GSTM1 and anemia: RFE-selected features comprised items related to renal function, such as age, uric acid, blood urea nitrogen (BUN), triglyceride, anemia-related factors (hemoglobin [Hb], hematocrit [Ht], and erythrocyte count), and blood pressure–related factor (right ankle DBP [RADIA])47–52 (Fig. 7a).