Two decades of surgical randomized controlled trials: worldwide trends in volume and methodological quality

In this systematic review, including 1188 surgical RCTs from 3 individual years in the past two decades (1999, 2009, and 2019), the worldwide volume remained stable in the past decade, whereas the rate of RCTs with a low risk of bias increased from 14.7 to 22.1 per cent, leaving ample room for improvement. The volume of published surgical RCTs increased in Asia, remained stable in North America, and decreased in Europe. Lay Summary An RCT is a form of research in which patients are divided randomly into two or more treatment groups to allow a fair and unbiased comparison of both treatments. RCTs are essential in guiding clinical decision-making, but are difficult to perform, especially in surgery. This review assessed the trend in volume and quality of published surgical RCTs over two decades. Surgical RCTs published in 1999, 2009, and 2019 were identified. The main outcome measures were volume of RCTs and trials with a low risk of bias. Different forms of bias can occur when research results are influenced by external factors. Some 1188 surgical RCTs were identified, of which 300 were published in 1999, 450 in 2009, and 438 in 2019. The volume of surgical RCTs published in these years increased mostly in Asia (61, 159, and 199 RCTs), especially in China (7, 40, and 81). In 2019, the countries with highest relative volume of published surgical RCTs were Finland and the Netherlands. Between 2009 and 2019, the proportion of RCTs with a low risk of bias increased from 14.7 to 22.1 per cent (P = 0.004). In 2019, the proportion of trials with a low risk of bias was highest in Europe (30.5 per cent), with the UK and the Netherlands as leaders in this respect. The volume of published surgical RCTs worldwide remained stable in the past decade but their methodological quality improved. Considerable geographical shifts were observed, with Asia and especially China leading in terms of volume. Individual European countries are leading in their relative volume and methodological quality of surgical RCTs. Background RCTs are essential in guiding clinical decision-making but are difficult to perform, especially in surgery. This review assessed the trend in volume and methodological quality of published surgical RCTs over two decades. Methods PubMed was searched systematically for surgical RCTs published in 1999, 2009, and 2019. The primary outcomes were volume of trials and RCTs with a low risk of bias. Secondary outcomes were clinical, geographical, and funding characteristics. Results Some 1188 surgical RCTs were identified, of which 300 were published in 1999, 450 in 2009, and 438 in 2019. The most common subspecialty in 2019 was gastrointestinal surgery (50.7 per cent). The volume of surgical RCTs increased mostly in Asia (61, 159, and 199 trials), especially in China (7, 40, and 81). In 2019, countries with the highest relative volume of published surgical RCTs were Finland and the Netherlands. Between 2009 and 2019, the proportion of RCTs with a low risk of bias increased from 14.7 to 22.1 per cent (P = 0.004). In 2019, the proportion of trials with a low risk of bias was highest in Europe (30.5 per cent), with the UK and the Netherlands as leaders in this respect. Conclusion The volume of published surgical RCTs worldwide remained stable in the past decade but their methodological quality improved. Considerable geographical shifts were observed, with Asia and especially China leading in terms of volume. Individual European countries are leading in their relative volume and methodological quality of surgical RCTs.