Table 1.
Categorization of the level of clinical evidence and strength of recommendation based on the EULAR standardized operating procedures for EULAR-endorsed recommendations (11, 12).
| Category | Evidence from |
|---|---|
| LEVELS OF EVIDENCE | |
| 1A | Meta-analysis of randomized controlled trials |
| 1B | At least one randomized controlled trial |
| 2A | At least one controlled study without randomization |
| 2B | At least one type of quasi-experimental study |
| 3 | Descriptive studies, such as comparative studies, correlation studies, or case–control studies |
| 4 | Expert committee reports or opinions and/or clinical experience of respected authorities |
| Grade | Directly based on |
| STRENGTH OF RECOMMENDATION | |
| A | Category 1 evidence |
| B | Category 2 evidence or extrapolated recommendation from category 2 evidence |
| C | Category 3 evidence or extrapolated recommendation from category 1 or 2 evidence |
| D | Category 4 evidence or extrapolated recommendation from category 2 or 3 evidence |