A one-minute rest period was given between groups of 3 trials to avoid fatigue.
Follow-up between the two groups of trials did not differ significantly (P=0.73).
Eleven trials remained (not 10 (37−27) because one trial recruited some participants with a recent infarct and some withoutw62); these recruited participants with a history of CHD but no recent infarct and in these the risk reduction was 13% (relative risk 0.87, 0.71 to 1.06; P=0.04 for the difference between the two groups of trials).
In contrast with the present study, a difference in study quality between the two groups of trials was seen; the mean percentage of items met in the consolidated standards of reporting trials (CONSORT) statement was lower for studies with surrogate outcomes than with final patient relevant outcomes (62.5 v 70.7, P=0.03).
Although an ICC ⩾0.90 is ideal for discriminating between groups of patients in a clinical trial setting, an ICC ⩾0.70 is acceptable (Fayers, 2004).
Still, we believe the comparison within each trial between groups of higher and lower Hb levels, whether by a definite transfusion trigger or by observed exposure to different Hb levels, is valid.
For each explanation we therefore split the trials into groups according to that characteristic, allowing us to partition the total heterogeneity into that seen 'within' and 'between' groups of trials.
For each explanation the trials were split into groups according to that characteristic, in order to partition the total heterogeneity into that seen 'within' and 'between' groups of trials.
One can suppose that differences between groups of homogeneous patients included in pivotal trials and real-life patients routinely admitted to the ICU may prevent guideline generalization.
In the present study, selected biochemical (protein, Fe and Cu), haematological (CBC and WCDC) and antioxidant enzyme (SOD, GPX) parameters remained within the published values and did not differ statistically significantly between groups of growers before and after the feeding trial.
Similarly, sleep efficiency and the percentage of time spent in a given stage of NREM sleep did not vary significantly between groups during completion of Trial 1 or Trial 2 (Table 2).
