We sought to determine whether there are differences in enrolled patients' risk factors in published percutaneous coronary intervention (PCI) trials between various continents.Methods
We systematically identified clinical trials evaluating PCI interventions through PubMed. We reviewed 701 studies between 1990 and 2014 from North America (N = 135), Europe (N = 403), and Asia (N = 163), examining the prevalence of cardiovascular risk factors—hypertension (HTN), diabetes mellitus (DM), hyperlipidemia (HL), smoking, sex, and body mass index. We performed meta-regression with random- and mixed-effects models to compare patient baseline characteristics between continents and linear meta-regression analysis to test trends over time.Results
In meta-regression with random-effects model, North American trials recruited the lowest proportion of male participants (71.32%), followed by Asian (74.41%) and European trials (76.47%; P < .0001). North American trials enrolled the highest proportion of patients with HTN (63.17%, P = .0035) and HL (63.72%, P < .0001), whereas Asia enrolled the highest proportion of DM patients (29.64%, P < .0001) and smoking (38.41%, P = .0144). When adjusting for other moderators such as publication date, body mass index, and sex in meta-regression with mixed-effects model, age was significantly positively correlated with HTN, HL, DM, and smoking (P < .001). Body mass index was significantly higher in Europe and North America than in Asia. All enrollment risk factors demonstrated (β < 0.02) statistically significant temporal trends over time, except for sex.Conclusions
There are major continental differences in risk factors among patients enrolled in PCI trials from various continents. Clinical trial results may not be applicable to patient populations from another region.