A meta-analysis of all controlled clinical trials of beta-adrenoceptor blocking drugs, principally propranolol, in the prevention of primary or secondary variceal bleeding has shown that beta-blockade significantly reduced the occurrence of variceal bleeding, deaths from variceal bleeding, and overall mortality. There was some heterogeneity between trials in the effect of beta blockade on secondary prevention. When only fully reported, randomised, placebo-controlled studies were included the heterogeneity disappeared, and the reductions in bleeding episodes and mortality became more striking. Separate analyses of primary and secondary prevention studies also showed clear reductions in occurrence of variceal bleeding and deaths. These results seem to indicate the value of beta-adrenoreceptor blocking drugs for the primary prevention of haemorrhage from large oesophageal varices. However, there is still a need for large multicentre trials of beta-blockade for primary prevention of variceal bleeding in patients without large varices and of comparisons between beta-blocker therapy with other treatments in secondary prevention.

80 reports of randomised clinical trials in four leading general medical journals were reviewed. The reporting of the methodology of randomisation was inadequate. In 30% of trials there was no clear evidence that the groups had been randomised. Among trials that used simple randomisation the sample sizes in the two groups were too often similar, and there was an unexpected small bias in favour of there being fewer patients in the experimental group. The handling of comparisons of baseline characteristics was inadequate in 41% of the trials. Suggestions are made for improving standards.