MONTREAL — A “surprising” and “provocative” study of two cohorts of women who developed peripartum cardiomyopathy (PPCM) in Canada and in the United States suggests that socioeconomic factors — differences in the healthcare systems — rather than genetics may explain racial disparities in outcomes.
The findings should be viewed as only hypothesis-generating, the authors caution.
Maxime Tremblay-Gravel, MD, from Université de Montréal, Canada, who is now a heart failure fellow at Stanford University, Palo Alto, California, presented findings from a study that involved 114 women in Canada and the United States (including 24 African Americans) who developed PPCM. The study was presented here at the Canadian Cardiovascular Congress 2019.
“It’s been pretty accepted in the literature…that African American women who have PPCM have a worse prognosis,” Tremblay-Gravel told theheart.org | Medscape Cardiology.
But contrary to previous research, their study showed that in Canada, recovery of left ventricular ejection fraction (LVEF) among black women after PPCM was similar to that among women of other ethnicities.
On the other hand, LVEF recovery among the African American women in the American cohort was dampened, consistent with prior findings.
“I don’t think African American women are different between the United States and Canada,” said Tremblay-Gravel. He noted that it’s probably the healthcare delivery that’s different.
This is “clearly only a hypothesis,” he continued, but many socioeconomic factors may explain why African American women with PPCM in the United States fared worse than their counterparts in Canada.
In the United States, women who developed PPCM may have had “less insurance, less education, [and] less trust in the medical care system…whereas here, we have a universal healthcare system.”
This is very topical, he noted, as candidates for the Democratic Party leadership are proposing that the United States adopt Medicare for all, “which is basically a system that would be a little bit more similar to Canada.”
“Interesting, Provocative, but Small”
“This small study is interesting and provocative in suggesting both that the differences in outcomes between African American vs non–African American women relates to socioeconomic status rather than race and that healthcare in Canada addresses these issues better than in the US,” Zolt Arany, MD, PhD, Perelman School of Medicine, University of Pennsylvania, Philadelphia, told theheart.org | Medscape Cardiology in an email.
Arany, who was senior author of a previously reported US study involving 121 African American and 99 non–African American women with PPCM, cautioned that “the numbers are very small, however, making a false positive conclusion not unlikely, and larger studies are needed.”
The findings “indicate that the differences in genetic background are not the main reasons for differences observed in LV recovery,” Johann Bauersachs, MD, professor and director of the Department of Cardiology and Angiology, Hannover Medical School, Germany, told theheart.org | Medscape Cardiology in an email
Bauersachs, who wrote a commentary that accompanied the article by Arany and colleagues, agreed that the cohorts in the current study were small.
“I suspect,” he suggested, that black women “have better access to healthcare services in Canada than African Americans in the US.”
According to Bauersachs, the results “clearly indicate that all efforts should be made to guarantee the same optimal care for African American as for non–African Americans with PPCM, both in the acute and the chronic phases.”
He is lead author of a recently published position statement from the Heart Failure Association of the European Society of Cardiology that summarizes diagnosis and optimal care for patients with suspected PPCM.
Is It the Genes or the Healthcare System?
Peripartum cardiomyopathy is “a potentially life-threatening condition typically presenting as heart failure with reduced ejection fraction (HFrEF) in the last month of pregnancy or in the months following delivery in women without another known cause of heart failure.
“It is a very rare disease, affecting 1 in 4000 young women who are pregnant,” Tremblay-Gravel noted.
“Most women recover, but some don’t,” he said, “and it’s a very underrecognized disease.
“As shortness of breath, fatigue, and leg [edema] are common in the peripartum period, a high index of suspicion is required to not miss the diagnosis,” the authors of the European position paper advise.
“We were interested in knowing whether being an African American portends a worse prognosis because of socioeconomic factors or because the disease itself is worse in African Americans,” Tremblay-Gravel said.
The Canadian cohort comprised 62 women, including 16 African American women (35%), who were treated for PPCM in hospitals in the province of Quebec during 1994–2015.
The American cohort consisted of 52 women with PPCM, including eight African American women (15%), who were seen at Stanford Hospital during 1991–2017.
The mean ages of the women in each of the cohorts were similar, at around 32 years.
In the Canadian cohort, improvements in LVEF were similar among African American and non–African American women, from 30% to 55% and from 28% to 52%, respectively (P = .27).
In the American cohort, improvement in LVEF among the non–African American women was similar to that of the Canadian women (going from around 30% to 50%), although for African American women, recovery of LVEF function was less (from around 25% to 38%; P = .02).
The next steps in their ongoing research, Tremblay-Gravel said, is to see whether insurance coverage and social status (estimated from ZIP codes) play a role in prognosis. They are also performing whole-exome sequencing for more than 100 women with PPCM to see whether African American women have a different genotype.
Canadian Cardiovascular Congress 2019: Abstract 060, presented October 24, 2019.