Australian New Zealand Clinical Trials Registry: history and growth.

The problem of publication bias and the need for prospective trial registration to overcome this issue has been recognised for many years. Australia and New Zealand established a national clinical trials registry, the Australian New Zealand Clinical Trials Registry (ANZCTR, http://www.anzctr.org.au), in 2005. Much progress has been made over the past six years on this important research infrastructure resource, with the ANZCTR now housing over 5330 registered trial records. Recent reviews and initiatives have helped encourage prospective registration of Australian/New Zealand trials but several challenges remain. We continue to work to ensure all those interested in clinical trials being conducted in Australia and New Zealand (including consumers, clinicians, researchers, funders and regulators) are able to access information that is comprehensive, complete, current and compatible.