A systematic review suggests that ethnic and regional patients are often under-represented in lipid lowering trials yet still derive benefits.
Despite being under-represented in randomised controlled trials of lipid lowering therapy, a systemic review has found that ethnic patients and those from different geographical regions still benefit from these treatments according to a systematic review by UK and Australian researchers
The benefits of LDL cholesterol-lowering treatment as a preventative strategy against atherosclerotic cardiovascular disease is now well established. Nevertheless, it has been recognised that differences in response between Caucasian and other ethnic patients to lipid lowering does occur.
For example, one comparative study revealed how the dose of statins and the extent to which LDL-cholesterol is reduced, varied between white and Asian patients.
Other work has shown that plasma levels of rosuvastatin and its metabolites are significantly higher in Chinese, Malay, and Asian-Indians compared to white patients.
Despite these known differences, what is less clear, is if this impacts on the incidence of adverse cardiovascular outcomes.
In the current study, researchers undertook a systemic review and meta-analysis of randomised clinical trials, to assess the reductions in cardiovascular events associated with lipid-lowering therapy in not only ethnic patients but different geographic regions.
They included statins, ezetimibe and PCSK9 inhibitors and set the outcome of interest as major adverse cardiovascular events (MACE) which was a composite of cardiovascular mortality, myocardial infarction, stroke and revascularisation.
Ethnic patients and MACE
A total of 53 trials including 329,897 participants with a mean age of 61.8 years (73% male) were included in the analysis. In the trials which reported ethnicities, 60.3% were White, 20.2% Japanese, 9.4% Asian, 5.5% Black and 4.7% Latin American.
When looking across regions, there were reductions in statistically significant reductions in MACE in Australasia (Risk Ratio, RR = 0.75), North America (RR = 0.75), Europe (RR = 0.78) and Japan (RR = 0.73).
When considering ethnicities, there were significant reductions among Black patients (RR = 0.55, 95% CI 0.37 – 0.82) and Japanese (RR = 0.73, 95% CI 0.63 – 0.85) but a non-significant reduction among Asians (RR = 0.76, 95% CI 0.54 – 1.08). In head to head comparisons between regions and different ethnicities, there were no significant differences in the extent of MACE reduction.
The authors concluded that while there was under-representation in clinical trials, ethnic patients and those from different regions appeared to derive at least as much cardiovascular benefit from lipid-lowering therapy as majority groups.
Citation
Sawant S, Wang N. Underrepresentation of ethnic and regional minorities in lipid-lowering randomized clinical trials: a systematic review and meta-analysis. Eur J Prevent Cardiol 2023.
