Credit: Bill Branson
Forgetting to take medication is the number one reason for non-adherence to maintenance therapy in children with acute lymphoblastic leukemia (ALL), according to a new study by the Children’s Oncology Group.
And neglecting to take maintenance medication 10% of the time increases the patient’s risk of relapse threefold.
In a study of 298 children receiving 6-mercaptopurine (6MP) as part of maintenance therapy, African Americans and Asians had significantly lower adherence rates than non-Hispanic whites, at 46%, 28%, and 14%, respectively.
Researchers discovered a number of other race-specific characteristics to explain the disparity, including low maternal education, households with a single parent and multiple children, low-income households, and households in which mothers were not the full-time caregivers.
The investigators had studied adherence in Hispanic children in an earlier study and they were not included here.
“While we don’t yet know why children of different races have significantly different survival rates for ALL,” said senior study author Smita Bhatia, MD, MPH, of City of Hope in Duarte, California, “we know that their adherence to their maintenance medication is a critical factor in their survival.”
And so the researchers explored potential sociodemographic differences that impact adherence to 6MP and reported their findings in Blood.
They enrolled 298 children, with a median age of 6 years at study entry (range, 2-20 years). All were in first continuous remission and receiving maintenance therapy that included 6MP.
One-hundred fifty-nine patients were non-Hispanic whites (the referent group), 71 were Asians, and 68 African Americans.
The researchers recorded adherence for up to 5 months per patient using an electronic monitoring device (MEMS®TrackCapTM) that recorded the date and time the pill bottle was opened. These data were downloaded at the end of the adherence-monitoring period.
They also measured erythrocyte TGN levels of the patients on a monthly basis to determine the association between bottle opening and taking the 6MP. Erythrocyte TGN levels reflect 6MP exposure.
Demographics
The researchers found that disease characteristics were comparable across the racial groups, but sociodemographic characteristics varied significantly.
African American families (64%) reported annual household incomes of less than $50,000 compared with 44% of non-Hispanic white and 33% of Asian families.
African American parents had significantly less formal education than non-Hispanic white and Asian parents. Sixty-six percent of African American fathers and 61% of African American mothers reported having less than a college degree.
This compared with 48% and 31% of non-Hispanic white and Asian fathers, respectively, and 46% and 32% of non-Hispanic white and Asian mothers, respectively.
More African American households (37%) were headed by single parents, compared with non-Hispanic white (9%) and Asian (4%) households.
And only 27% of African American children had their mothers as full-time caregivers, compared with 38% of non-Hispanic white children and 52% of Asian children.
Overall adherence
The investigators found that adherence for the entire population declined over the course of the 5 months, from 94.8% to 91.3% (P<0.0001).
Adherence rates were significantly lower in Asians and African Americans than in non-Hispanic whites, and in patients from low-income households.
Adherence rates were significantly higher in patients from single-parent/single-child households (96.9%) and in households where the mothers were full-time caregivers (94.8%).
Adherence by race
In Asian households, adherence was significantly higher with mothers as full-time caregivers (95.6%) compared with all other configurations of caregivers. And adherence rates in households with income of $50,000 or more were also higher (93.9%) than in households with income under $50,000 (84.2%).
In African American households, those with low maternal education had significantly lower adherence rates, 74.6%, than in those households in which mothers held a college degree, 94.6%. And adherence rates were higher in households with single parents and a single child (94.2%) compared with those households with a single parent and multiple children (80.5%) or even from nuclear families (85.5%).
In non-Hispanic white households, paternal education higher than a postgraduate degree resulted in adherence of 97.2%, compared with households in which the father did not have a postgraduate degree, (95.3%). Again, adherence rates were higher in households with single parents and a single child (97.8%) compared with those from single parents with multiple children (94.0%) or from nuclear families (95.6%).
For all racial groups, forgetfulness was the most common reason for missing doses—non-Hispanic whites, 79%; Asians, 90%; and African Americans, 75%.
“Our data demonstrate that one in four children in remission from ALL does not take the medicine needed to remain cancer free,” said Dr Bhatia, “and in an overwhelming majority, the primary reason why is that they forget to take their pills each day,” said Dr. Bhatia.
“These results are the basis for further studies that will examine how physicians can successfully intervene, using technology, for example, to ensure that children do not experience an increased risk of relapse because they did not take their oral chemotherapy.”
