For Alzheimer's disease researchers who conduct clinical trials, enrolling enough patients to make a trial meaningful is always a challenge. To enroll a single patient in a study requires not one but two participants - the patient and what's known as a study partner. Study partners provide the patient with support and update researchers about the patient's progress.
A new UCLA study has assessed the prevalence of the various types of study partners in Alzheimer's clinical trials - a patient's spouse or "other" partners, like a patient's adult child - and has discovered that who the study partner is can actually impact the results of the trials and the interpretations of those results.
The study appears in the Dec. 19 online issue of the journal Neurology.
"The role of the study partner is vital to the success of Alzheimer's disease clinical trials," said the study's first author, Joshua D. Grill, an assistant professor of neurology at UCLA and a member of the UCLA Mary S. Easton Center for Alzheimer's Disease Research. "We count on them to ensure that the patient is taking their medications, drive them to appointments and, in general, report back how things are going."
In their analysis of 2,041 Alzheimer's patients who had participated in six clinical trials, Grill and his colleagues found that 67 percent of these patients had a spouse as their study partner. Yet in the general population, more than two-thirds of all unpaid Alzheimer's disease caregivers are patients' children, children-in-law or grandchildren, and half of unpaid caregivers are under the age of 50.
And importantly, the researchers said, as many as 90 percent of Alzheimer's sufferers don't have spouses.
"But two-thirds of clinical trial participants do have spouses," Grill said. "That confirms we are missing a huge population of people we are not enrolling. They're out there, and we need to do a better job of recruiting them in order to expedite study of promising drugs for Alzheimer's."
The team also found that, after controlling for confounding factors, the risk of dropout for the "other" study partner group - the group including adult children - was 70 percent higher than for the spouse study partner group.
Grill added that factors such as race of the patient and the attitudes of caregivers can also impact recruitment for clinical trials.
For example, only 5 percent of participants in the clinical trials the researchers looked at were Hispanic, and only 6 percent were African American. Those trial participants who had an adult child as their study partner were twice as likely as those with spouse partners to be Hispanic and nearly three times as likely to be African American.
"Typically in Alzheimer's disease trials, we don't know if there are differences between minority patients and Caucasians in terms of a drug's possible effectiveness," Grill said. "But if we can do a better job with enrolling Alzheimer's patients who have non-spousal study partners, we may get better with recruiting minorities as well, so that we can answer that type of question."
The current study doesn't explain why clinical trial participants with non-spouse study partners were underrepresented. Adult-child study partners were more likely to be working and living apart from the patient, Grill said, "so it might simply be a question of logistics. But this will require further study."