Ssince 2007, obstetricians have counseled patients who plan to give birth after a previous cesarean section using a simple calculator designed to determine the likelihood of having a successful vaginal birth after a cesarean, or VBAC.
The tool takes into account the patient’s age, height, weight and history of vaginal and cesarean delivery. He also asks two yes or no questions: “African American? “Hispanic?” The responses can predict a significantly lower chance of success for patients of color. But now, after years of work by researchers, advocates and clinicians, that racialized calculator has been replaced with a new validated version it is the same in almost all respects, except to eliminate race and ethnicity as a risk factor.
The VBAC calculator is just one of many clinical algorithms that have recently been challenged for their use in breed adjustment. Providers in all specialties questioned the inclusion of race and ethnicity – which are social, not biological factors – in their decision-making tools, underscoring the risk of perpetuating existing health inequalities. But as obstetricians access the VBAC calculator online, it might turn out to be much easier than with other patched tools to quickly use the updated calculator nationwide.
“I think it’s powerful that this is, in some ways, the first example of racial correction routinely dropped in a tool in response to these fairness issues,” said Darshali Vyas, resident of Massachusetts General Hospital.
Vyas first noticed how running was incorporated into the VBAC calculator in 2017, as she was finishing her rotation in obstetrics while training at Harvard Medical School. She shared her concerns with a mentor and published in 2019 a paper with colleagues at Brigham and Women’s Hospital who took issue with the use of race in the calculator, which was developed by the Maternal-Fetal Medicine (MFMU) Network.
“They put it there because the results based on societal and structural norms that lead to these differences appear epidemiologically,” said Audra Meadows, co-author of the article who was previously medical director of outpatient obstetrics at BWH. “But in the end, it hurts the option of trying to have a vaginal birth.”
This, in turn, could disproportionately steer patients of color toward a potentially riskier procedure, reinforcing extreme inequalities in maternal medicine: Black women are three to four times more likely to die from pregnancy-related causes than women. white women, a disparity attributed in part to higher rates of cesarean sections. Although a new cesarean section is a safer choice than labor for many patients, a successful VBAC reduces the maternal risk of blood transfusion, unplanned hysterectomies, and trips to the ICU.
With the updated calculator, Meadows said, “we can now have another way to safely promote vaginal birth by not convincing someone that they need a calculator-based cesarean.”
It’s not clear whether the original calculator itself contributed to poorer outcomes for patients of color, or whether the updated version will change care for the better. The tool does not offer a binary directive, yes or no; it only adds up the odds of a similar patient having a successful VBAC, a datum clinicians can use to inform their conversations with patients.
Yet “it became clear that this was conceptually not something we wanted to continue to have in the perpetual model, that it was important not to have a socially constructed variable – race, ethnicity – in a predictive model.” because of the potential negative consequences. “said William Grobman, OB-GYN at Northwestern and lead author of the MFMU team that developed the initial and updated ECUs.
“This is a really critical recognition by the medical community that we got it wrong,” said Michelle Morse, chief medical officer for the New York City Department of Health and Mental Hygiene and deputy commissioner of the Center for Health Equity and Community Wellness. “And it’s a recognition that we haven’t always been transparent, frankly, about how the system shapes the clinical questions we ask.”
Some obstetricians had previously recognized these errors independently, choosing not to enter a patient’s race and ethnicity into the original calculator and defaulting to “African American” and “Hispanic” responses to. ” no “.
The analysis behind the updated tool confirms this choice, showing that it works with same level of precision like the previous version. The updated calculator also includes a new objective clinical variable: whether or not a patient has been treated for chronic hypertension.
“This is an example to me that our clinical tools can remain scientifically rigorous and still clinically useful without correcting for race,” said Vyas.
The updated calculator is far from perfect, Grobman admitted. In order to demonstrate that the calculator’s predictive value was the same with or without race, he and his colleagues constructed it from two decades old data on the same set of patient outcomes. And the new calculator has not yet been validated externally in other contexts and countries.
Nicholas Rubashkin, clinical professor of obstetrics, gynecology and reproductive sciences at UCSF, also noted that the calculator is still a black box. “Although this new calculator does not include race / ethnicity, the authors did not tell us about the distribution of racial / ethnic groups in the score ranges,” he said in an email. . And even a deracialized tool can reinforce care gaps if not used with care. Although the calculator was never intended as a screening tool, Rubashkin’s research indicates that some doctors use a VBAC calculation result of 60-70% as a cut-off, refusing to offer the option to patients who achieve a. lower score.
“There is still work to be done to repair the damage caused by the use of this tool around the world since 2007,” said Rubashkin.
Outside of AVAC, work to critically assess the role of race and ethnicity in clinical algorithms is ongoing. In 2020, Vyas and other colleagues highlighted several examples of clinical algorithms that include correcting for race in the New England Journal of Medicine. In response, House Ways and Means Committee Chairman Richard Neal called professional medical societies to control their use of race and medicine in their tools.
Since then, medical societies and individual provider systems have made efforts to eliminate race and ethnicity from their practices. In March of this year, for example, the American Society of Nephrology and the National Kidney Foundation officially recommended ending the practice of racial adjustment of estimated glomerular filtration rate, a measure of kidney function that may play a role. a critical role in determining whether or not a patient receives a kidney transplant.
But turning this recommendation into practice will require sustained advocacy from trainees and clinicians, Vyas said. “This eGFR tool is used in individual hospital labs,” she said. “There is a big gap between this recommendation and the actual implementation of the change. “
The VBAC calculator, however, is generally accessible by physicians online, which could allow for a more systematic and rapid change. the old tool is always the first result of an online search for “VBAC calculator”. But its content has been removed and replaced with a link to the Updated version. While many vendors had previously issued internal guidelines for omitting the calculator’s race and ethnicity, enforcing these policies has been difficult; removing the old tool in its entirety does the job for them.
“It’s not our responsibility to just drop something,” Grobman said. “It is our responsibility then to help disseminate this information. “
In order for the new tool to maximize its impact, Morse called for more transparency on the part of its developers to recognize the motivation to reconsider tools that include race and ethnicity. She will also seek immediate advice from professional societies such as the American College of Obstetricians and Gynecologists to describe how the new tool should be implemented. “I think it has the potential to have more impact at the systems level,” said Morse. “But the proof is in the pudding.”
And updating the calculator is a small step in the process of building an equitable health care system. Only a small number of patients have the choice of having a VBAC, and many other factors contribute to the disparity in cesarean section rates and maternal morbidity and mortality. Given the inequalities of care embedded in obstetric practices in the United States, Meadows is skeptical that the change of calculator will have a significant impact on these harms.
“It’s about righting the wrongs of medicine more than improving outcomes,” she said.