Cancer and cardiovascular disease fair well, but research trials for mental health and musculoskeletal conditions don’t meet the burden of disease.
Research into some conditions falls short relative to burden of disease, according to a report on Australian clinical trial activity.
Investigators from the University of Sydney’s NHMRC Clinical Trials Centre examined Australian trials registered on the ANZCTR or clinicaltrials.gov from 2006-2020.
They found that cancer, which has the highest burden of disease at around 18% of total burden of disease, had the highest number of trials (20% of total) and second highest number of participants (around 16% of total), outnumbered only by cardiovascular disease.
Cardiovascular disease, which comprises around 14% of total burden of disease (second highest after cancer), had fewer trials than would be expected, accounting for 12% of all trials. However, the number of total participants was higher and accounted for the highest proportion of trial participants among all conditions (20%).
The biggest loser was musculoskeletal conditions. The analysis found that the number of musculoskeletal trials accounted for around 9% of all trials, while the number of participants in these trials accounted for around 5% of total trial participants.
Meanwhile, the burden of disease for musculoskeletal conditions is 13% of total burden, with the authors suggesting that compared with burden of disease, musculoskeletal trial activity is lower than would be expected.
Other conditions potentially underrepresented in clinical trials relative to burden of disease are mental health and neurological trials, at least in terms number of participants. In terms of number of trials, the pattern is consistent with burden of disease for those conditions.
Trials investigating inflammatory and immune system conditions, including rheumatoid arthritis, connective tissue diseases, autoimmune diseases and allergies, accounted for 5% of all trials and 4% of trial participants. There were no AIHW burden of disease data provided for this disease group.
Skin conditions (not including cancers), with around 2% burden of disease, comprised around 3% of number of trials, increasing to 4% in more recent years (2016-2020), although the number of participants is in line with what would be expected relative to burden of disease.
The researchers also considered types of trials conducted. Most (75%) looked at treatment strategies, of which drug trials were the majority (45% of all trials; 60% of treatment trials). Other treatments were devices (11% of all trials), surgery (4%) and ‘Other’ (20%) including exercise, physiotherapy, cognitive therapy, special diets, herbal medicines and web-based treatments.
There were relatively few trials looking at diagnosis/prognosis and early detection/screening, with each comprising about 2% of all trials.
In all, there were almost 20,000 trials and almost nine million participants (which includes overseas participants in some trials) over the study period.
The authors noted that clinical trial activity in Australia rates quite well compared with other OECD countries, with higher per capita involvement than the US, UK, France and Germany, but lower than Belgium, Denmark and the Netherlands.
The authors highlighted several areas for improvement, particularly data sharing and the opportunity to contribute to the open science movement.
“Since October 2018, the International Committee of Medical Journal Editors and the World Health Organization (WHO) have required trialists to state whether they plan to share de-identified data at the time of registration,” the authors wrote in the MJA.
“Since then, only 485 (23%) of 2143 Australian trials have indicated the intention to share data. Internationally, rates are similar, with 23% of trials on the WHO trials platform intending to share data.”
