To remove the effect of rescue medication, data were analyzed after excluding patients who took a rescue medication before the scheduled time point of outcome measurement.
From an assessment of predetermined considerations regarding study characteristics (e.g., species, route of exposure, method of outcome measurement, time point of outcome measurement), we determined that 7 of these studies (8 data sets), all of which exposed pregnant mice to PFOA via gavage treatment and measured weight of offspring at or soon after birth, were suitable for meta-analysis.
Restriction to a homogeneous study population (1 point) b) Comparability of relevant baseline characteristics: duration of complaint (1 point), value of outcome measures (1 point), age (1 point), recurrences (1 point), and radiating complaints/associated symptoms (1 point) c) Description of the randomization procedure (2 points).
Small changes have been made to the protocol over time, to reflect changes in points of outcome data collection and recruitment procedures.
Therefore, it may be useful to include several intermittent time points of outcome evaluation in order to track the patterns of changes as outcomes may change rapidly and may or may not be sustained.
We assessed heterogeneity by visual inspection of graphs and χ test for homogeneity (at 10% level of significance) and explained heterogeneity by exploring differences in drug doses or durations, severity of enteric fever (as defined by investigators), and time points of outcome measurement.
The NOQ is used to appraise quality in terms of population representativeness (1 point), measurement of outcome (i.e. discontinuation, 3 points), within population comparability (2 points) and adequacy of follow-up (i.e. completion rates, 1 point, only applicable in longitudinal studies).
From this point of view, outcome measures reflect the patient's subjective perspective whereas an objective measure would be unbiased by the patient's state of mind.
Interestingly, the risk scores generated based on the 12-marker aggressiveness model were equally predictive for the separate end point of lethal outcome across tissue-sampling variation.
The following information was extracted from each paper: sample size; number of health care providers; data collection time points; number of outcome measures; methods of determining change in health status.
RCTs focus on the difference between point estimates of outcomes for entire groups (control and experimental), using statistical tests of significance to show that differences between the two arms of a trial are not likely to be due to chance.
