Lower-Income Patients Less Likely to Participate in Clinical Trials

Beth Fand Incollingo @fandincollingo
Published: Tuesday, Sep 04, 2012
Joseph M. Unger

Joseph M. Unger, PhC

Patients with cancer who have lower incomes are less likely to participate in clinical trials, according to a large national survey presented at ASCO 2012.

The findings held true even in patients aged >65 years, who are nearly universally covered by Medicare, showing that access to health insurance did not necessarily affect decision making about trial participation, said the study’s lead author, Joseph M. Unger, PhC, a health services researcher and statistician with the SWOG Statistical Center at the Fred Hutchinson Cancer Research Center in Seattle, Washington.

“When we adjusted for income, education, age, race, sex, distance to clinic, and patient medical conditions, income was the only socioeconomic status or demographic factor that remained an independent predictor of clinical trial participation,” Unger said. “From the patient’s perspective, since clinical trials offer state-of-the-art treatments, this finding raises concern about whether all income levels have equal access to trials, and from the clinician’s and researcher’s perspective, better participation of lower-income patients could speed the conduct of clinical trials and better assure applicability of clinical trial results across all income levels.”

The study included 5499 adults newly diagnosed with breast, lung, colorectal, or prostate cancer who were surveyed following their treatment decisions between 2007 and 2011. Patients filled out the study questionnaire while visiting cancer-related informational websites.

The study found that patients who reported annual incomes of <$50,000 were about 30% less likely to participate in a clinical trial than those reporting incomes ≥$50,000. Patients who made <$20,000 a year were 44% less likely to participate in clinical trials than those who made ≥$20,000 a year.

Of all the patients surveyed, 40% discussed clinical trials with their physicians. A greater proportion of patients earning ≥$50,000 per year reported that their doctors had broached the subject of clinical trials than did patients earning <$50,000 (42% vs 36%). In all, 45% of the discussions led to offers of clinical trial participation, and 51% of offers led to enrollment in a clinical trial. The overall clinical trial participation rate was 9%.

The study also found that concern about how to pay for clinical trial participation was much higher among lower-income patients. Fifty-three percent of patients earning ≤$20,000 were concerned about how to pay for their trial, while only 24% of patients earning ≥$100,000 shared that concern, Unger said.

Treatment in clinical trials typically does not cost more than nontrial cancer treatment, the researcher said. While the study did not assess the specific cost concerns that led patients to decide against participating in trials, Unger said, barriers may include direct costs, such as copays and coinsurance, or indirect costs, such as having to take time off work to go for a clinic visit, though these costs are also borne by people undergoing cancer treatment outside of clinical trials.

Unger praised the study’s design, saying it was “the largest I know of that includes both patientspecific income data and patient-specific comorbidity rates. Having both together in a large study gave us a lot of power to identify income as a factor that’s independently associated with reduced clinical trial participation for lower-income patients.”

A limitation of the study was that, since it was conducted among people who regularly used the Internet, its cohort was younger and less diverse than the general cancer population, Unger said.

When we adjusted for income, education, age, race, sex, distance to clinic, and patient medical conditions, income was the only socioeconomic status or demographic factor that remained an independent predictor of clinical trial participation.”
–Joseph M. Unger, PhC
SWOG researchers will now attempt to confirm the findings by analyzing data from a previous prospective study of barriers to clinical trial participation. That study was designed to look at the issue of age but included information about patient income, Unger said.

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