Data from the PLATINUM DIVERSITY trial, which was presented at the 2016 Transcatheter Cardiovascular Therapeutics (TCT) meeting (29 October–2 November, Washington DC, USA), indicates that the risk of death or myocardial infarction after percutaneous coronary intervention (PCI) is significantly higher among women and minorities than it is among white men. Furthermore, the risk of post-PCI myocardial infarction is significantly increased among minorities.
Wayne Batchelor (Florida State University College of Medicine, Southern Medical Group, Tallahassee, USA) told TCT delegates that the aim of PLATINUM DIVERSITY was to address the lack of available data for women and minorities undergoing PCI, noting that “whites account for 64% of the US population but 85–90% of the PCI volume and patient enrolment in clinical trials”. He added that he and his colleagues sought to determine “if there are significant differences in one-year clinical outcomes between women and minorities compared with white men in the era of second-generation drug-eluting stents”.
Pooling data from the PLATINUM DIVERSITY cohort (1,501 self-identified female and minority patients) and the Promus Element Plus PAS cohort (2,687 patients), Batchelor et al found 4,188 patients—of these, 1,863 were women, 1,635 were white men, and 1,059 were minorities. All patients had undergone PCI with an everolimus-eluting permanent polymer stent (Promus, Boston Scientific). The primary endpoint was the one-year composite endpoint of death, myocardial infarction, and target vessel myocardial revascularisation. Secondary endpoints include death, myocardial infarction, target vessel revascularisation, a composite of death/myocardial infarction, and a composite of death/probable stent thrombosis.
According to Batchelor, there were significant differences between groups at baseline. Women and minorities were, on average, older, had more diabetes, and had more hypertension than white men whereas white men were more likely to present with acute coronary syndromes. There were also significant differences in the percentage of patients on dual antiplatelet therapy after PCI, with significantly more white men on dual antiplatelet therapy at 12 months than women or minorities—but Batchelor noted that these differences were “numerically small, only 3%”. Despite these differences, the rate of the primary endpoint was similar among groups—8.6% for women and 9.6% for minorities vs. 7.6% for white men (p=0.33 and p=0.08, respectively).
However, when Batchelor et al examined the individual components of the primary endpoint, they found that death was significantly increased in women (3.4% vs. 2.2% for white men; p=0.04) and there was a trend towards increased myocardial infarction (1.9% vs. 1.1%; p=0.06). For minorities, death (3.7%; p=0.03) and myocardial infarction (3.1%; p=0.0002) were both significantly increased compared with white men. Target vessel revascularisation was not significantly increased in either women or minorities. Given the imbalances in baseline characteristics between the three groups, the investigators performed a prespecified multivariate analysis that showed the combined risk of death and myocardial infarction was still significantly increased in both women (odds ratio 1.6; p=0.01) and in minorities (odds ratio 1.9; p=0.004).
Batchelor commented that because there were no significant differences among groups in the rate of target vessel revascularisation or in the rate of definite/probable stent thrombosis “device failure is unlikely to account for the observed differences”. He added: “These results highlight the heterogeneity conferred by sex and race and suggest further study into the biologic, social, behavioural, and economic factors that impact cardiovascular risk after a drug-eluting stent.”
A second aim of the PLATINUM DIVERSITY trial is, Batchelor reported, to “characterise and evaluate the impact of social/behavioural/economic determinants of health and minorities”. “A lot factors could be playing a role here [as to why there were differences between groups]. The potential influence social and economic factors will be really interesting to discover,” he concluded.
Batchelor told Cardiovascular News: “PLATINUM DIVERSITY is the first study thus far to use a unique ‘enriched enrolment’ design to help close a longstanding research gap that exists within interventional cardiology. My hope is that this will help provide a catalyst for other stakeholders involved in cardiovascular research to be more creative in the way we design and perform clinical cardiovascular outcomes studies that are more reflective of the US population.”