San Diego, CA—New research sponsored by the National Cancer Institute highlights the uphill battle faced by patients with limited financial resources even in clinical trials. According to data presented at the 2019 ASCO Quality Care Symposium, patients with Medicaid or with no insurance had significantly worse overall survival in positive clinical trials compared with privately insured patients.
This meta-analysis of data collected from 19 clinical trials and more than 11,000 patients showed that underinsured patients had no observed benefit from experimental treatment in trials that had positive overall survival benefits. By contrast, positive treatment effects were observed for all other groups of patients.
“The magnitude of treatment benefits from experimental therapies may not be uniform for patients with Medicaid or no insurance,” said lead author of the study, Joseph M. Unger, PhD, SWOG Statistics and Data Management Center, Fred Hutchinson Cancer Research Center, Seattle, WA. “These patients are likely at a greater risk of experiencing competing risks of death, which can reduce power to identify the benefits of new experimental therapies.”
Understanding whether benefits are consistent among all patient groups is critical for informing clinical guidelines, but clinical trials are rarely powered to examine demographic or insurance subpopulations, especially in underrepresented groups.
“The generalizability of treatment effects to these subgroups is often simply assumed, and distinctions about treatment efficacy within subgroups are rarely made in cancer treatment guidelines,” said Dr Unger.
For this study, Dr Unger and colleagues examined whether positive treatment effects apply to all demographic and insurance groups. The researchers pooled data from all SWOG treatment trials completed between 1985 and 2014 with a statistically significant (P <.05) overall survival benefit in the experimental arm. They then looked at private versus Medicaid or no insurance status. Suboptimal insurance status was an indicator of low socioeconomic status at the patient level. Multivariable Cox regression models were used to identify whether survival patterns differed by demographic and insurance status factors.
The final analysis included 19 trials with significantly better overall survival in the experimental arm, for a total sample size of more than 11,000 patients. Although overall survival treatment effects did not differ by sex, race, or ethnicity, patients with private insurance had a much greater benefit from the experimental therapy compared with patients with Medicaid or no insurance.
“One key takeaway is that underinsured patients had no observed benefit from the experimental therapy in trials where everybody else essentially had that benefit,” said Dr Unger, who noted that analysis of progression-free survival showed similar discrepancies.
Follow-up time from 0.1 year to 7.5 years was used to see when the interaction between insurance status and treatment became significant. The role of insurance status manifested itself very quickly within the first year of follow-up, he said.
“Thereafter, there’s nearly a constant influence of insurance status on treatment effects over time,” said Dr Unger. “Although this effect is more meaningful for overall survival than it is for progression-free survival, the effect is statistically significant for both end points within the first year.”
“Even in a setting in which patients are uniformly staged and treated under protocol care, suboptimal insurance influenced both cancer and noncancer outcomes,” Dr Unger concluded. “These findings may inform policy regarding continued resource support for patients beyond their initial treatment.”
Nina A. Bickell, MD, MPH, Co-Director, Center for Health Equity and Community Engaged Research, Icahn School of Medicine at Mount Sinai, New York, NY, said that these findings highlight the critical role of social determinants of health on clinical trial outcomes and the likely role of comorbidities.
“Although clinical trials frequently exclude individuals with certain comorbidities like congestive heart failure, other comorbid conditions that could affect overall survival may not be excluded,” said Dr Bickell, noting that access and adherence to treatments—not just for cancer, but for all of an individual’s medical challenges—can also affect survival.
In addition to making it easier for providers and patients in underserved communities to access clinical trials, researchers must also make sure that patients have insurance to help with comorbidity treatments, as well as with clinical trial costs, Dr Bickell said.
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