Study participants with comorbid tuberculosis (AOR: 2.50, 95% CI: 1.82–3.42), anaemia (AOR: 1.30, 95% CI: 1.12–1.52), CD4 counts ≤ 200 cells/μL (AOR: 1.46, 95% CI: 1.26–1.68), viral load ≥ 100,001 copies/ml (AOR: 1.36, 95% CI: 1.17–1.58), and WHO Clinical stages 3 and 4 (AOR: 1.54, 95% CI: 1.33–1.79) at presentation to the ART clinic were more likely to have gained weight at their 6-month follow-up clinic visit. Here, CD4 is linked to anemia (phenotype).