PPA might be an independent risk factor for long-term mortality after adjusting baseline characteristics (including baseline Hb, adjusted OR: 1.3, 95% CI: 1.1–1.6, P = 0.023), but whether PPA or baseline anemia plus PPA is a stronger predictor than baseline anemia should be discussed in future researches. This evidence concerns the gene GSTM1 and anemia (phenotype).