Ethnic patients benefit from lipid lowering despite under-representation in trials

3rd March 2023

A review suggests that while ethnic and regional patients are often under-represented in lipid lowering trials they still derive benefits

Ethnic patients and those from different geographical regions benefit from lipid-lowering therapy despite being under-represented in clinical trials, 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. Despite this recognition, some evidence points to differences in response between Caucasian and other ethnic patients. 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. However, while there are apparent ethnic differences in response to lipid lowering therapy, 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 PCSK 9 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