Table 1.
Synopsis of grading systems used in the respective guidelines
| Grading | Ref | |
|---|---|---|
| ATS | ||
| Level I (high) | Evidence comes from well-conducted, randomized, controlled trials | 5 |
| Level II (moderate) | Evidence comes from well-designed, controlled trials without randomization (including cohort, patient series, and case-control studies). Level II studies also include any large case series in which systematic analysis of disease patterns and/or microbial etiology was conducted, as well as reports of new therapies that were not collected in a randomized fashion | |
| Level III (low) | Evidence comes from case studies and expert opinion. In some instances, therapy recommendations come from antibiotic susceptibility data without clinical observations | |
| BSAC | ||
| A | At least one meta-analysis, systematic review, or RCT rated as 1++ and directly applicable to the target population; or a body of evidence consisting principally of studies rated as 1+, directly applicable to the target population, and demonstrating overall consistency of results | 7 |
| B | A body of evidence including studies rated as 2++, directly applicable to the target population, and demonstrating overall consistency of results; or extrapolated evidence from studies rated as 1++ or 1+ | |
| C | A body of evidence including studies rated as 2+, directly applicable to the target population and demonstrating overall consistency of results; or extrapolated evidence from studies rated as 2++ | |
| D | Evidence level 3 or 4; or extrapolated evidence from studies rated as 2+ | |
| Good clinical practice points | ||
| Recommended best practice based on the clinical experience of the guideline development group | ||
| 1++ | High-quality meta-analyses, systematic reviews of RCTs, or RCTs with a very low risk of bias | |
| 1+ | Well-conducted meta-analyses, systematic reviews, or RCTs with a low risk of bias | |
| 1− | Meta-analyses, systematic reviews, or RCTs with a high risk of bias | |
| 2++ | High-quality systematic reviews of case control or cohort studies. High-quality case-control or cohort studies with a very low risk of confounding or bias and a high probability that the relationship is causal | |
| 2+ | Well-conducted case control or cohort studies with a low risk of confounding or bias and a moderate probability that the relationship is causal | |
| 2− | Case-control or cohort studies with a high risk of confounding or bias and a significant risk that the relationship is not causal | |
| 3 | Nonanalytic studies, eg, case reports, case series | |
| 4 | Expert opinion | |
| CCCTG | ||
| Level 1 | Randomized, controlled trials, blinded-outcome adjudication, intention-to-treat-analysis, explicit definition of VAP | 8,12 |
| Level 2 | Any condition mentioned above unfulfilled | |
| Level 3 | No randomization | |
| Recommend | “… if there were no reservations about endorsing an intervention.” | |
| Consider | “… if the evidence supported an intervention but there were minor uncertainties about the benefits, harms, or costs.” | |
| No recommendation | “… was made if evidence regarding an intervention was inadequate or if there were major uncertainties about the benefits, harms, and costs.” | |
| Do not recommend | “… if there was no evidence of benefit and there was potential for harm or increased healthcare costs from the intervention.” | |
| G-HAP | ||
| 1A | Strong recommendation, high evidence – desirable effects clearly outweigh risks or additional resource consumption or vice versa | 9 |
| 1B | Strong recommendation, moderate evidence | |
| 1C | Strong recommendation, low or very low evidence | |
| 2A | Weak recommendation, high evidence – desirable effects possibly outweigh risks or additional resource consumption or vice versa | |
| 2B | Weak recommendation, moderate evidence | |
| 2C | Weak recommendation, low or very low evidence | |
| 3 | No recommendation – no clear indication for presence of benefit or risk | |
| PEG | ||
| A | Ia evidence based on meta-analyses of RCT | 11 |
| A | Ib evidence based on at least one RCT | |
| B | IIa evidence based on at least one well-designed controlled study without randomization | |
| B | IIb evidence based on at least one well-designed quasi-experimental study | |
| B | III evidence based on well-designed nonexperimental studies (eg, case-control study) | |
| C | IV evidence based on expert opinions, results of consensus/conferences | |
Abbreviations: ATS, American Thoracic Society; BSAC, British Society for Antimicrobial Chemotherapy; CCCTG, Canadian Critical Care Trials Group; G-HAP, S3-Guideline for hospital acquired pneumonia in Germany PEG, Paul-Ehrlich-Gesellschaft; RCT, randomized, controlled trial; VAP, ventilator-associated pneumonia.