Risk of bias assessment
| Category | Criteria | Study | ||
|---|---|---|---|---|
| Brooks et al (1972)7 | Christiaens et al (2002)8 | Ferry et al (2004;9 200710) | ||
| Defined sample | Description of source of patients, and inclusion and exclusion criteria | Yes | Yes | Yes |
| Representative sample | Participants selected as consecutive cases | Yes | Not reported | Not reported |
| Follow-up rate | Outcome data available for at least 80% of participants at one follow-up point | Yes | Yes | 57% at 5–7 weeks, but>80% at 8–10 days |
| Prognosis | Raw data, percentages, survival rates, or continuous outcomes reported | Yes | Yes | Yes |