Table 1 Levels of CEBM modified for scientific papers investigating disease pathophysiology with bench research.
From: Systematic review with meta-analysis: cytokines in fibromyalgia syndrome
Level | Differential diagnosis/symptom prevalence study | Blinded | Controls | Remark/example |
|---|---|---|---|---|
1a | Systematic review of prospective cohort studies | NR | NR | No systematic reviews available |
1b | Prospective cohort study with good follow-up | NR | Implicit | An item is assessed (e.g. breast implant) and the occurrence of FMS is followed prospectively |
1c | All or none case series | Test and assessment of results | Obligatory | All patients with low IL-4 have FMS, none has high IL-4 |
1d | 1c | Test or assessment of results | Obligatory | 1c |
2a | Systematic review (with homogeneity) of | NR | NR | No systematic reviews available |
2b and better studies | ||||
2b | Retrospective cohort study, or poor follow-up | NR | Implicit | FMS patients are investigated now, if they have had breast implants in the past; large size studies |
2c | Ecological studies | Test and assessment of results | Implicit | FMS patients are investigated simultaneously, if they have FMS and if they have low IL-4 levels. |
2d | 2c | Test or assessment of results | Implicit | 2c |
3a | Systematic review (with homogeneity) of 3b and better studies | No systematic reviews available | ||
3b | Non-consecutive cohort study, or very limited population | Test and assessment of results | Obligatory | FMS patients and controls (limited population) are now investigated if they have low IL-4 |
levels | ||||
3c | 3b | Test or assessment of results | Obligatory | 3b |
3d | 1c, 2c, 3b | Not blinded | Obligatory | |
4 | Case series or superseded reference standards | All studies without control group | Case series with historical controls; case reports | |
5 | Expert opinion without explicit critical appraisal, or based on physiology, bench research or "first principles" | NR |