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At a time when medical researchers are under pressure to increase diversity in clinical trials, a Johns Hopkins study is sparking outrage among some physicians because of its large number of Black patients.

The controversy has stoked concerns that the institution infamous for its role in the Henrietta Lacks story may have once again exploited marginalized people for medical research. The university denies any wrongdoing and instead said it was simply providing a service to its local community, which has a mostly Black population.

The paper was published last fall without much notice but caused a stir on social media in recent weeks. It was a retrospective study analyzing the abilities of three specially trained nurse practitioners to perform colonoscopies, an invasive and potentially lifesaving cancer screening procedure normally done by gastroenterologists. Of the more than 1,000 patients who received screening colonoscopies from the nurse practitioners between 2010 and 2016, nearly 75% were Black.


“That is a huge red flag because that could not have happened randomly,” said Fola May, a gastroenterologist at the University of California, Los Angeles. “Did they preferentially pick Black patients to be in the study and to get the NP colonoscopies?”

African Americans make up about 63% of Baltimore’s population and 88% of the Middle East Baltimore neighborhood where Johns Hopkins Hospital is located. But Black people account for only about 25% to 31% of the patients treated in the Hopkins hospital system, according to annual reports from 2015-2016 and 2017. Johns Hopkins did not provide racial demographics of the patients who undergo colonoscopies, but said it provides the procedure to people living in the local community and outside the community.


Amid projections that demand for colonoscopies will soar as the population ages and as colorectal cancers rise among younger people, the researchers wanted to find out whether nurse practitioners who completed a yearlong gastrointestinal training fellowship could perform colonoscopies up to the same standards as doctors. For comparison, a gastroenterologist typically completes three years of internal medicine residency and three years of a gastroenterology fellowship.

Critics of the study questioned whether the patients were adequately informed that nurses don’t commonly do the procedure in the U.S., and whether they were given a choice to have their exam done by a doctor.

“When I saw the paper, my immediate concerns were around informed patient consent,” said Rachel Issaka, a gastroenterologist at the Fred Hutchinson Cancer Research Center in Seattle. “I really wanted to know, were those patients told up front that their colonoscopy was being done by a nurse practitioner, because that’s not the standard of care in the United States.”

Anne Marie Lennon, who is director of the Johns Hopkins division of gastroenterology and hepatology and was not involved in the research, said the data from the study show that the nurse practitioners met the same national metrics for safety and effectiveness set for gastroenterologists performing screening colonoscopies.

“This is a service where it was offered to the community, and the community happened to be people of color,” Lennon told STAT. “The concept that … people think this is Hopkins sort of looking at and doing something that is incorrect or immoral — that is simply just not true.” She said patients could choose a nurse practitioner or a gastroenterologist when they called to make an appointment, and some may have opted for NPs because they typically had shorter waits.

The study was spearheaded by Anthony Kalloo, a gastroenterologist who preceded Lennon as director of gastroenterology and hepatology before his recent appointment as chair of the department of medicine at Maimonides Medical Center in Brooklyn, N.Y.

Kalloo told STAT the patients were informed that their procedure was being done by a nurse practitioner and that they did have the option to have it done by a doctor. None of the patients refused treatment by a nurse practitioner in favor of a gastroenterologist, he added. He said patients signed a standard consent form to undergo the colonoscopy and were not asked to explicitly acknowledge they understood their procedure was being done by a nurse practitioner as opposed to a doctor who would have had more training.

Kalloo started training nurse practitioners at Johns Hopkins Hospital to perform colonoscopies, he said, as a way to save money and give back to the community, as well as meet the rising demand for the procedure, especially in underserved areas and rural places where access to a gastroenterologist might be limited.

“My God, it’s such a no-brainer to me almost. Why wouldn’t you want to save costs, especially when you have demands for a procedure that’s increasing and increasing,” he said. “So the logical thing, in terms of supply and demand, would be to train nurse practitioners to do this.”

He chalked up the criticism from gastroenterologists to longstanding tensions between physicians and nurse practitioners over the growing scope of medical procedures that non-physicians are allowed to do. “It has a lot to do with the perceived conception that it’s a threat to their livelihood,” said Kalloo. “I expected a little bit of pushback, but I did not expect this degree of pushback.”

He compares it to complaints that emerged when certified registered nurse anesthetists began administering anesthesia to patients, and noted that nurse practitioners regularly perform colonoscopies in the United Kingdom. He said he was simply duplicating a procedure that happens elsewhere in the world, though in the U.S., the American Society of Gastrointestinal Endoscopy had published guidelines in 2009 that stated “there are insufficient data to support nonphysician endoscopists to perform colonoscopy. …”

“It’s flabbergasting that this is such an issue … this is nothing new,” he said. “Except we for the first time in this paper showed that we could do this in the U.S. and the implication of that is cost savings.”

On Twitter, May, at UCLA, suggested the Hopkins study was exploitative. She responded to a fellow gastroenterologist’s tweet by saying the paper was “fueling the woes and fears of experimentation and exploitation in the Black community yet again!”

She was not alone in her worries, as doctors from various specialties, health professionals, and others also voiced their concerns on social media.

“Feels a lot like medical experimentation (*cough* racism) to me,” wrote Jazmyn Shaw, an emergency room nurse and medical student.

“Trying to wrap my head around how they managed to get ~750 Black people to sign up for this. I can’t even convince family to get vaccinated,” tweeted Kerry Mitchell, a plastic surgeon at Ohio State University Wexner Medical Center.

“Two-tiered medical system here we come. ‘MD for me but not for thee,’” wrote Daniel Choi, an orthopedic surgeon at Spine Medicine and Surgery of Long Island.

Adding to the critics’ concerns was a 2015 study published by Kalloo and two colleagues that evaluated colonoscopies performed independently by a single nurse practitioner between 2010 and 2012. Of the 300 people in that study, nearly 85% were African American.

“What happened to all of the white patients that normally walk into Hopkins to get a colonoscopy?” May said in an interview. If the researchers wanted to ethically demonstrate that nurse practitioners can do high-quality colonoscopies, she said, they should have instead conducted a trial on a randomly selected group of patients. “You should start with all types of patients. You shouldn’t be targeting Black patients,” she said.

The patient makeup of the studies is particularly concerning to some because African Americans are disproportionately affected by colorectal cancer. They are 20% more likely to get colorectal cancer than white people and 40% more likely to die from it, according to the American Cancer Society. The American Society for Gastrointestinal Endoscopy says African Americans are also more likely to have advanced colon cancer when it is diagnosed, and to have polyps — abnormal tissue growths that could potentially become cancerous — deeper in the colon, where they can be harder to spot with a colonoscopy.

“Because their care is so complex, they need the gold standard,” said Ruqaiijah Yearby, a bioethicist at Saint Louis University. “They don’t just need somebody who was able to do it, they actually need somebody who can catch all of the problems that they may suffer because they’re at increased risk of a higher rate of disease, cancer, and death,” she said.

Kalloo defended his work against claims of racial exploitation, asserting the study would lead to better care and more access for patients of color seeking colonoscopies.

“I found those comments to be amusing,” said Kalloo. “Obviously, they saw that I was the lead author from Hopkins, but they obviously didn’t know what I look like,” he said. Kalloo is a Black man who was born in Trinidad.

“There was not a selective intent to seek out patients of minority [groups],” he added. “And as I said, I am a minority.”

The three nurse practitioners in the study performed at least 140 colonoscopies while supervised by a gastroenterologist during a fellowship program at Hopkins before they could perform the procedure independently. That amount was the minimum number of colonoscopies necessary to demonstrate competency, according to recommendations at that time from the American Society for Gastrointestinal Endoscopy. They also underwent a performance evaluation before being credentialed to perform the procedure on their own.

The paper noted that the nurse practitioners were women between the ages of 18 and 36. Two were white and one was Asian, and two held a master’s as their highest degree and one a doctorate. (STAT reached out to one of the nurse practitioners who was also the study’s lead author, but was referred by Johns Hopkins to speak with Lennon instead.)

Sophie Balzora, a gastroenterologist at NYU Langone Health, said 140 colonoscopies seemed very low to develop competency, and estimated that by the end of her three-year clinical fellowship at NYU, she had completed more than 800 colonoscopies.

“By the end of first year, you would have several hundred under your belt, and you still wouldn’t be comfortable performing procedure after procedure on your own without any supervision,” she said.

Some studies have suggested that colonoscopy competency comes after around 250-300 procedures and others around 500 procedures. In 2017, after the time frame of the Hopkins study, the American Society for Gastrointestinal Endoscopy raised its recommended minimum to 270 procedures for competency assessment.

A look at the Johns Hopkins gastroenterology and hepatology webpages from 2013 to 2016 suggests there were typically about 40 to 50 gastroenterologists and about 15 gastroenterology medical fellows on staff each year.

“You’re in a highly populated urban area where there are physicians who perform thousands of colonoscopies throughout their career, but then you’re having a colonoscopy done by an NP who has done only at least 140 procedures. Why is that?” Balzora said. “It’s a perfect example of systemic racism in my mind.”

Yearby, the Saint Louis University bioethicist, agreed that the study raises ethical issues. She said she doesn’t think the researchers targeted Black patients in the same way they were targeted in the Tuskegee syphilis study, or in a Hopkins HIV study in Ethiopia in which researchers cancelled plans to give pregnant women a placebo instead of the drug AZT to prevent HIV transmission to their babies, or the Hopkins Krieger study that evaluated interventions to reduce lead poisoning in children. But she called the procedures problematic for other reasons.

“They used a population because they were in an urban area at an academic medical center, and they had lots of people coming in who needed colonoscopies, and so they used that as an opportunity to try this out,” she said. “That is undue influence and targeting of particular populations.”

The nurse practitioners were permitted to work only at the hospital, according to Lennon. While they were performing on their own, there was always a gastroenterologist “on the floor,” Kalloo noted.

During the study period, the three nurse practitioners conducted a total of 1,425 colonoscopies. About 400 were excluded from the study because the patients either did not have clean enough bowels or they came in for screening and it was found they had a disease like inflammatory bowel disease, which led to a doctor taking over. The nurses detected adenomatous polyps in about 36% of cases, which exceeded the standard for detection of more than 25% of cases as set by the ASGE and the American College of Gastroenterology. The NPs also achieved cecal intubation, which is at the end of the colon, 98.5% of the time, which also met the national standards of higher than 95%. They did not cause any perforations of the colon.

“They can tout their results, but when they started the study they didn’t know what the results were going to be,” said May. She also took issue with the paper’s lack of follow-up. “They finished these colonoscopies over five years ago. Why not tell us how many of those patients have developed cancer in the interim?”

The study had several limitations. The use of only three nurse practitioners limits how much the results can be generalized to other nurse practitioners. It also did not say how many of the colonoscopies required the assistance of a physician to reach cecal intubation.

Kalloo said he struggled to get the work published in one of the more established GI journals, and ultimately published it in the journal Endoscopy International Open.

Johns Hopkins is no longer training nurse practitioners through its gastrointestinal fellowship to perform colonoscopies, Lennon said. Two of the three NPs involved in the study are now at different institutions, and the one still at Hopkins no longer does colonoscopies, she said. But Lennon asserted the program wasn’t stopped because of any concerns with it.

“There’s no insidious [reason], there’s nothing unusual about this. This is simply people have moved on,” she said. “It’s an interesting thing the prior division director did, but we’re not running this at the moment.”

Another factor in the Hopkins decision, Kalloo said, was the fact that Medicare and Medicaid don’t reimburse for nurse practitioners who perform colonoscopies. Still, he said he would be interested in starting up a similar gastrointestinal fellowship at his new medical center in Brooklyn to continue training nurse practitioners to conduct colonoscopies.

“I just got here at Maimonides four weeks ago, so I’m trying to get my feet wet,” Kalloo said. “It is something I would love to reinstate here. It’s just not going to happen tomorrow.”

  • Untrue. There are pushes to have NPs practice w/o supervision with no real evidence that NP care=Physician care. Studies like these do not mean anything unless patients are followed years after and will push cheaper/poorer care to minority patients based on bogus results. How do we know these patients haven’t developed cancer/what was missed? I’m happy they didn’t cause problems during the procedure, but doing them does not equate to doing them correctly and knowing what you are seeing. Also the ethical part of this is very fishy. Race was definitely playing a role. The numbers are pretty clear here.

  • This is sloppy reporting. For example, it reports what they raised the recommended minimum procedures *after* the trial, and what various people think it should be *now*, implying the training that nurses got was inadequate, but it doesn’t report what it was at the time of the trial. Here let me google it for you: it was 140 (, the same number that the nurses did during their training.

    • I’m confused. Are you using this article to support the 140 colonoscopy mark? Because the results of this 2010 study you linked showed that they needed >500. Also, the study was done in gastroenterology fellows who already have way more medical training than the NPs in this study. Sounds like they’re reporting was actually underestimating how many you need to have to be competent.

  • Now, we even have to exploit race to get our colons examined? Seems like it should have been a win-win as many patients received their exam. NPs are extremely skilled & knowledgeable and I’m sure a nurse anesthetist was administering the “conscious sedation “ as they give anesthesia in most hospitals as well. I don’t believe this was an “experiment “ but an effective tool to make safe colonoscopies available to all at a reasonable cost. Do you really think NPs operate w/out medical supervision?

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