Table 3. Sensitivity, specificity and predictive values of a loss in BMI, a loss in CD4 cells or both, for predicting virological failure at 6 months.
| Loss in BMI and/or CD4 | No. of patients (N)a | No. with virological failure (n)b | Se (%) | Sp (%) | PPV (%) | NPV (%) |
|---|---|---|---|---|---|---|
| Loss in BMI | ||||||
| < –4 kg/m² | 2 | 0 | 0 | 99 | 0 | 84 |
| < –3 kg/m² | 6 | 1 | 1 | 99 | 17 | 84 |
| < –2 kg/m² | 23 | 4 | 4 | 96 | 17 | 84 |
| < –1 kg/m² | 61 | 8 | 8 | 90 | 13 | 84 |
| < 0 kg/m² | 140 | 23 | 23 | 78 | 16 | 84 |
| Loss in CD4 | ||||||
| < –150/μl | 2 | 0 | 0 | 99 | 0 | 84 |
| < –100/μl | 6 | 1 | 1 | 99 | 17 | 84 |
| < –50/μl | 29 | 6 | 6 | 96 | 21 | 84 |
| < 0/μl | 67 | 18 | 18 | 90 | 27 | 85 |
| Combined losses | ||||||
| < –1 kg/m² and < –50/μl | 8 | 1 | 1 | 99 | 13 | 84 |
| < 0 kg/m² and < 0/μl | 25 | 9 | 9 | 97 | 36 | 85 |
BMI, body mass index; CD4, CD4+ T-cell count; NPV, negative predictive value; PPV, positive predictive value; Se, sensitivity; Sp, specificity. a No. of patients in whom the gain in BMI and/or the gain in CD4 is higher than the corresponding threshold at 6 months. b No. of patients with undetectable viral load at 6 months.