Randomised controlled trials have shown that statins improve the survival of patients with ischaemic heart disease.1–5 Although combinations of drugs (as proposed in the Polypill)6 have been received with enthusiasm, we found no direct evidence evaluating the effects of statins, aspirin, β blockers, and angiotensin converting enzyme inhibitors in combination.
Uncritical acceptance of medical innovations or lack of evidence can result in the endorsement of ineffective or potentially dangerous treatments, subsequently leading to the withdrawal of drugs (for example, rofecoxib) or limitations on use.7–9 Limitations on use can occur years after worldwide adoption, as was the case with hormone replacement therapy.10 Although randomised trials provide relatively unbiased evidence of the effectiveness of interventions in selected patients, the application of trial results to representative populations of patients is often inaccurate.11 In addition, further trials can be difficult, or even unethical if a true benefit is suspected.
Routinely collected data from aggregated general practice databases have been used successfully to evaluate the risks and benefits of treatments in a population.12 13 This method enables access to longitudinal data, to a large sample size, and to representative populations. Also, because data on exposure can be collected before the outcome occurs, recall bias is limited; the quality of the electronic record now surpasses that of the paper based system.14
We determined the effect of combinations of drugs in the secondary prevention of all cause mortality in patients with ischaemic heart disease in a large UK population based sample.