Comorbidities Associated with Lower Clinical Trial Participation


Patients with cancer who have other health issues are less likely to have discussions about – and participate in – clinical trials.

Patients with cancer who also have other health issues are less likely to participate in a clinical trial, potentially leaving gaps in understanding how drugs may affect individuals with certain comorbidities, according to recent research published in JAMA Oncology.

Researchers from the SWOG Cancer Research Network examined data of nearly 5,500 patients from a national survey and found that an increase in comorbidities — including high blood pressure, asthma or a prior cancer – was associated with fewer discussions about joining a clinical trial, clinical trial offers and participation.

Traditionally, patients with other diseases were excluded from clinical trials because their condition might affect the efficacy of the therapy being evaluated, and therefore, skew outcomes. However, inclusion criteria for many clinical trials may soon be expanding, allowing for the participation of well-managed comorbidities — thanks to efforts led by the American Society of Clinical Oncology (ASCO), friends of Cancer Research and the Food and Drug Administration (FDA).

“Both patients and researchers will benefit from the modernization of trial eligibility criteria. First and foremost, it allows trials to be more inclusive, so that patients with a more diverse clinical profile can have access to the newest treatments available in clinical trials for their care,” said study author Joseph Unger, Ph.D., MS, from the SWOG Statistical Center and assistant member of the Public Health Sciences Division at the Fred Hutchinson Cancer Research Center.

Despite the potential benefits and efforts spearheaded by three leading organizations in the oncology space, individuals with other illnesses are still far less likely to participate in clinical trials than their healthier counterparts. Those with comorbidities were 15 percent less likely to have a discussion with their care provider about a trial, 23 percent less likely to have trials offered by their provider and 24 percent less likely to actually participate in a trial.

Unger, who is also an affiliate assistant professor of health services research at the University of Washington, noted this is a major issue considering how many patients have other diseases or conditions.

“Our own study showed that two out of three cancer patients have at least one comorbid condition in addition to their cancer,” he explained. “The rate is even higher in older patients where both cancer and other chronic diseases are more common.”

This is not the first research to show that clinical trial participation may not be a level playing field. It has also been shown that patients with lung cancer who come from a lower socioeconomic status are less likely to be offered the latest treatments or be enrolled in a clinical trial.

Having more patients enroll in clinical trials not only benefits those participating, but it could also lead to quicker advances in the cancer space.

“Allowing cancer patients with comorbid conditions to enroll in trials will make trial recruitment go more quickly,” Unger said. “Ultimately, this will allow us to complete trials more quickly.”

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