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Table 3 Distribution of studies by quality scoring values according to the Chalmers et al. method

From: Prevention of ventilator-associated pneumonia, mortality and all intensive care unit acquired infections by topically applied antimicrobial or antiseptic agents: a meta-analysis of randomized controlled trials in intensive care units

Quality items Adequate*
Research protocol N. %
Description of inclusion and rejection criteria for patient selection (28) 23 82
Number and description of patients eligible not accepted (28) 16 57
Daily amount and timing of therapeutic regimen (28) 26 93
Physical appearance of placebo/control similar to the treatment (21) 16 76
Taste of placebo/control similar to the treatment (21) 10 48
Description and appropriate use of methods for assuring masking of randomization (28) 21 75
Patients masked treatment (27) 18 67
Observers masked to treatment (27) 17 63
Observers masked to results (28) 6 21
Prior estimate of sample size and power calculation (28) 15 54
Definition of criteria for stopping the trial (28) 11 39
Test of validity of randomization through description of relevant demographic and prognostic variables in experimental and control group (28) 24 86
Methods used to evaluate success of masking (20) 15 75
Methods used to ascertain compliance to treatment (0) - -
Laboratory tests to evaluate absorption or pharmacological effect of the treatment (16) 2 13
More than one observer evaluating subjective endpoints (23) 2 19
Data analysis and presentation   
Start and stop dates (28) 20 71
Analysis of results of randomization through baseline comparability of the study groups (28) 17 61
Presentation of test statistics and P-value (28) 26 93
Discussion of ß error in negative trials (17) 3 18
Calculation of estimate of variance and/or confidence limits of trials endpoints (28) 10 36
Regression/correlation analysis (25) 12 48
Overall assessment of quality of statistical analysis (28) 1 4
Number of patients who withdrew and the reasons why (28) 25 89
Ways withdrawals were handled (23) 1 4
Side effects reported and analyzed (28) 6 21
Analysis of subgroups not specified at the beginning of the study (retrospective analysis) (28) 2 7
  1. Number of studies for which item was applicable in parenthesis
  2. *Completely addressed the issue