Quality assessment of included trials and potential sources of bias
| Blinding to treatment allocation | Drop outs/losses to follow up | Other | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Study | RP | Pt | Pr | OA | Total (n) | IG (n) | CG (n) | Reasons given? | PC? | HS? | Comments |
| RP, randomisation process used; Pt, patient; Pr, provider; OA, outcome assessor; IG, intervention group; CG, control group; PC, power calculation reported; HS, hypothesis stated a priori; NR, not reported or unclear. | |||||||||||
| Antitussives | |||||||||||
| Taylor et al9 | NR | Yes | Yes | NR | 8/57 (14%) | NR | NR | Yes | Yes | Yes | Post hoc power calculation shows that study was powered to detect a difference of 0.9 in cough score which is equivalent to natural resolution of cough at day 3. Authors argue that smaller reductions in cough scores are unlikely to be clinically important. |
| Mucolytics | |||||||||||
| Nespoli et al10 | NR | Yes | Yes | Yes | NR | NR | NR | No | No | No | High likelihood of bias. |
| Antihistamine–decongestant combinations | |||||||||||
| Clemens et al11 | NR | NR | Yes | Yes | NR | NR | NR | No | Yes | Yes | Patients stated to be “randomly assigned in a double blind fashion”. |
| Hutton et al12 | NR | Yes | Yes | Yes | 12/96 (12.5%) | 6/36 (16.6%) | 3/27 (11.1%) | Yes | Yes | Yes | Some children in open treatment group (n=9) and drug group (n=3) took other medication. |
| Other combinations | |||||||||||
| Reece et al13 | NR | Yes | NR | NR | NR | NR | NR | No | No | No | High likelihood of bias, medication sponsored by medical director of a laboratory who also performed the analyses. |
| Antihistamines | |||||||||||
| Sakchainanont et al14 | NR | Yes | Yes | Yes | 7/150 (4.6%) | NR | NR | Yes | No | Yes | Bonferroni correction for multiple comparisons used. |