Australian clinical trial activity and burden of disease: an analysis of registered trials in National Health Priority Areas.

Objective: To assess whether Australian clinical trials activity in National Health Priority Areas (NHPAs) reflects the relative disease burden. Design and setting: Analysis of trials registered on the Australian New Zealand Clinical Trials Registry (ANZCTR) or ClinicalTrials. gov from January 2008 to December 2012 that planned recruitment in Australia and investigated interventions for NHPA conditions (cancer control, cardiovascular health, mental health, obesity, injury prevention/control, diabetes mellitus, arthritis and musculoskeletal conditions, dementia and asthma). Australian estimates of disability-adjusted life-years (DALYs) were used to quantify the burden of disease for each NHPA. Main outcome measures: For each NHPA, the total number of registered trials, planned recruitment, and the predicted numbers based on disabilityadjusted life-years expressed as a proportion of the total burden of disease in Australia (% DALY). Results: 5143 trials with Australian sites were registered in the 5-year study period with total planned recruitment of 2 404 609 participants. Of these, 3032 trials (59%) with planned recruitment of 1 532 064 participants (64%) investigated NHPA conditions. Trial numbers and planned recruitment were highest for cancer, cardiovascular and mental health reflecting their higher disease burden. In contrast, planned recruitment into obesity and dementia trials was <= 50% of that predicted from total trial activity based on their relative disease burden. The number of registered trials for these conditions was also lower than predicted. Overall, of 3032 NHPA trials, 2335 (77%) used randomisation and 1520 (50%) planned to recruit > 100 participants. Conclusions: Australian clinical trial activity for obesity and dementia interventions is lower that would be expected based on their relative disease burden. Trial registries provide a valuable public database to identify and monitor gaps in research