Mixed-effect multivariate logistic regression model showed an increased risk of anaemia worsening in patients with higher D0 parasitaemia (AOR 1.65, 95% CI 1.52–1.79, p = 0.001) and Hb (AOR 1.57, 95% CI 1.51–1.63, p = 0.001), younger age (AOR 0.95, 95% CI 0.94–0.97, p = 0.001, per year of age). This evidence concerns the gene GSTM1 and anemia.