Summary of findings 2. Vitamin A compared to placebo.
| Vitamin A compared to placebo for adults with HIV infection currently taking ART or not | ||||||
| Participant or population: adults with HIV infection Settings: any Intervention: vitamin A (single dose or daily dose) Comparison: placebo | ||||||
| Outcomes | Illustrative comparative risks* (95% CI) | Relative effect (95% CI) | Number of participants (trials) | Certainty of the evidence (GRADE) | Comments | |
| Assumed risk | Corresponding risk | |||||
| Placebo | Vitamin A | |||||
| Mortality | — | — | — | (0 trials) | — | — |
| Morbidity | — | — | — | (0 trials) | — | — |
| CD4 cell count (cells/mm³) Follow‐up: 6 to 8 weeks | — | — | Not pooled | 464 (2 trials) | ⊕⊕⊝⊝
low1,2,3,4 due to risk of bias and indirectness |
Vitamin A may have little or no short‐term effect on CD4 cell count |
| Viral load (log10copies/mL) Follow‐up: 6 to 8 weeks | — | — | Not pooled | 495 (3 trials) | ⊕⊕⊝⊝
low1,2,3,4 due to risk of bias and indirectness |
Vitamin A may have little or no short‐term effect on viral load |
| Change in vitamin A concentrations (µmol/L) Follow‐up: 6 to 8 weeks | — | — | Not pooled | 495 (3 trials) |
⊕⊕⊝⊝
low1,3,4,5 due to risk of bias and indirectness |
Vitamin A may increase blood concentrations of persons with HIV with low baseline concentrations |
| *The basis for the assumed risk (for example, the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% CI) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). Abbreviations: ART: antiretroviral therapy; CI: confidence interval; RR: risk ratio. | ||||||
| GRADE Working Group grades of evidence High certainty: further research is very unlikely to change our confidence in the estimate of effect. Moderate certainty: further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate. Low certainty: further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate. Very low certainty: we are very uncertain about the estimate. | ||||||
1Downgraded by 1 for serious risk of bias: one trial in Kenya with 400 participants reported high attrition overall (11.5%) and the trial authors stated that participants who were lost to follow‐up had more advanced HIV disease and were more likely to be vitamin A deficient (Baeten 2002 KEN). 2No serious heterogeneity: none of the trials found statistically significant effects. 3Downgraded by 1 for serious indirectness: trials were conducted in the USA and Kenya, and most participants were not on antiretroviral therapy (ART). This may not completely exclude the possibility of effects in some settings or populations. 4No serious imprecision: no statistically significant differences were seen. Although two trials were underpowered, one trial in Kenya with 400 participants was adequately powered to reliably detect a clinically beneficial effect on CD4 cell count, viral load, and blood vitamin A concentrations (Baeten 2002 KEN). 5No serious heterogeneity: a statistical significant increase in blood vitamin concentrations was reported in one trial from Kenya with 400 participants. Baseline blood vitamin concentrations of these participants were much lower than the 95 participants in the other two trials in the USA.