The type and quality of randomized controlled trials (RCTs) published in UK public health journals

Background Randomized controlled trials (RCTs) are increasingly being used to evaluate the effectiveness of health care interventions. Systematic reviews of RCTs form the basis of the Cochrane Collaboration, which aims to synthesize all RCTs concerned with the provision of health care. This paper reports the quantity and methodological quality of RCTs published in five UK public health journals, which were searched as part of a planned register of RCTs in public health. Methods Five journals were hand searched: The International Journal of Epidemiology, Health Trends, Journal of Public Health Medicine, Public Health and The Journal of Epidemiology and Community Health. All RCTs were identified and their methodological characteristics reviewed. Results Ninety-one trials were identified from the five journals. A wide variety of topics were covered, the most common being prevention strategies (46 per cent of the trials). Although the actual number of reports of RCTs published increased over time, there was no detectable improvement in the quality of reports. The aspect of bias most well controlled was control of bias at entry (randomization), in 83 (91 per cent) of trials. However, even in these trials details about the process of randomization were poor. Conclusion These trials will form the basis of a register of RCTs in public health. The diversity of topics covered illustrates the broad-based nature of public health. For this reason, many other RCTs relevant to the practice of public health are likely to be found in non-public-health journals.