| 
   TB–tuberculosis; IR – Incidence rate; 95% CI – 95% Confidence interval; py – person years; d4T – Stavudine; AZT- Zidovudine. Totals for Drug contraindication (n=24,
 21.2%); Toxicity (n=85, 75.2%); Treatment failure (n=2, 1.8%); Other reasons (n=2, 1.8%).
  | Reason for modification | Overall | d4T in regimen | AZT in regimen |  
  | Drug Contraindication, IR (95% CI) | 10.3 per 100py (6.9-15.4) | 10 per 100py (5.6-18.1)
 | 10.6 per 100py (6.1-18.2) |  
  | TB treatment | 18 | 6 | 12 |  
  | Pregnancy | 6 | 5 | 1 |  
  | Toxicity / Side-effects, IR (95% CI) | 5.9 per 100py (4.8-7.3) | 5.1 per 100py (4-6.5)
 | 11 per 100py (7.2-16.7) |  
  | Peripheral neuropathy | 29 | 29 | 0 |  
  | Lipodystrophy / lipoatrophy | 27 | 26 | 1 |  
  | Anaemia | 6 | 0 | 6 |  
  | Hypersensitivity rash | 9 | 2 | 7 |  
  | Hepatitis / raised transaminases | 8 | 3 | 5 |  
  | Lactic acidosis | 3 | 3 | 0 |  
  | Vomiting | 2 | 0 | 2 |  
  | Myalgia | 1 | 0 | 1 |  
  | Treatment failure, IR (95% CI) | 4.9 per 100py (1.2-19.5) | 4.9 per 100py (1.2-19.5)
 | - |  
  | Treatment failure | 2 | 2 | 0 |  
  | Other reasons, IR (95% CI) | 53.3 per 100py (13.3-213.3) | 53.3 per 100py (13.3-213.3) | - |  
  | Drug shortage | 2 | 2 | 0 |  
  | Total, IR (95% CI) | 1 per 100py (0.8-1.2) | 1.2 per 100py (0.9-1.5)
 | 0.7 per 100py (0.5-1) |  
  | Total | 113 | 78 | 35 |  |