CD4 and anemia (phenotype): In the adjusted multivariate flexible parametric model, the independent risk factors for attrition were: BMI<18.5 [HR 2.06, 95% CI: 1.76 to 2.40]; WHO stage III or IV at baseline [HR 2.01, 95% CI: 1.58 to 2.57]; anaemia at baseline [HR 1.80, 95% CI: 1.41 to 2.30], and baseline CD4 count <100 cells/μl [HR 1.74, 95% CI: 1.50 to 2.01].