Summary of findings for the main comparison. Antibiotic versus no drug or placebo for Shigella dysentery.
| Antibiotic versus no drug or placebo for Shigella dysentery | ||||||
| Patient or population: patients with Shigella dysentery Settings: Mexico and Bangladesh Intervention: Antibiotic versus no drug or placebo | ||||||
| Outcomes | Illustrative comparative risks* (95% CI) | Relative effect (95% CI) | No of Participants (studies) | Quality of the evidence (GRADE) | Comments | |
| Assumed risk | Corresponding risk | |||||
| Control | Antibiotic versus no drug or placebo | |||||
| Diarrhoea on follow up ‐ Furazolidone versus no drug clinical criteria Follow‐up: 6 days | 58 per 100 | 12 per 100 (5 to 28) | RR 0.21 (0.09 to 0.48) | 73 (1 study) | ⊕⊝⊝⊝ very low1,2,3 | Antibiotic sensitivity of Shigella isolates not reported; Trial done in 1989 |
| Diarrhoea on follow up ‐ Cotrimoxazole versus no drug clinical criteria Follow‐up: 6 days | 58 per 100 | 17 per 100 (9 to 34) | RR 0.3 (0.15 to 0.59) | 76 (1 study) | ⊕⊝⊝⊝ very low1,2,4 | Same trial as above; had three arms |
| Relapse ‐ not reported | See comment | See comment | Not estimable | ‐ | See comment | The two trials for this comparison were too short in follow up duration (6‐7 days) to estimate relapses and none were reported. |
| Serious adverse events ‐ not reported | See comment | See comment | Not estimable | ‐ | See comment | None of the two trials for this comparison reported serious adverse events |
| Other adverse events clinical criteria Follow‐up: 7 days | 0 per 100 | 0 per 100 (0 to 0) | RR 1.43 (0.06 to 34.13) | 94 (1 study) | ⊕⊝⊝⊝ very low5,6,7 | Data from a three armed trial; only one non‐serious adverse event in the antibiotic arms and none in placebo arm |
| *The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: Confidence interval; RR: Risk ratio; | ||||||
| GRADE Working Group grades of evidence High quality: Further research is very unlikely to change our confidence in the estimate of effect. Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate. Low quality: 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 quality: We are very uncertain about the estimate. | ||||||
1 Very serious limitations: The method of randomization was not described and there were baseline imbalances in duration of diarrhoea. Allocation concealment and blinding were not reported and this increases the risk of bias in the detection and reporting of some adverse events, though not for other primary outcomes that were objectively ascertained. 2 Serious indirectness: The single trial included only children and hence the evidence for effectiveness of antibiotics over no antibiotics in adults is uncertain. Though the trial did not exclude participants who were malnourished, it is unclear if any participant was malnourished. 3 No imprecision: Both limits of the point estimate of the trial indicated benefit with furazolidine over not receiving an antibiotic 4 No imprecision: Both limits of the point estimate showed appreciable benefit with cotrimoxazole over not receiving an antibiotic 5 Very serious limitations: Allocation was not concealed and there were baseline imbalances in antibiotic sensitivity to those allocated to ceftriaxone (100%) and ampicillin (80%) 6 Serious indirectness: The trial randomized only adults. The antibiotics assessed were ceftriaxone and ampicillin. 7 Very serious imprecision: The 95% CI of the point estimate of the trial includes appreciable risk of adverse events for antibiotics over placebo with no significant differences between interventions.