One factor associated with increased likelihood of adherence to medications for comorbid conditions was greater contact with a primary care physician. Breast cancer survivors who saw their primary care physicians two or more times during year 2 post diagnosis were 70% less likely to be nonadherent to antihypertensive therapy than were those who visited their primary care physicians less frequently.
Greater body mass index was associated with significantly less likelihood of nonadherence to antihypertensive agents but not statins or diabetes medications. When researchers used a BMI below 25 kg/m2 for reference, patients with a BMI of 25-29.9 were 39% less likely to be nonadherent to antihypertensive therapy, those with a BMI of 30-34.9 kg/m2 were 46% less likely, and women with a BMI of 35 kg/m2 or greater were 63% less likely to be nonadherent to their antihypertensive therapy.
A higher Charlson comorbidity score of 2 or more during the first year following breast cancer diagnosis was associated with a 51% reduction in likelihood of nonadherence to diabetes medications during year 2 and a 46% lower nonadherence rate for statins than in patients with a Charlson score below 2.
As reported in previous studies of non-cancer patients, younger age was associated with increased nonadherence. This was true across the board for all three medication classes, although the age effect was most dramatic with respect to nonadherence to statins and oral diabetes medications. Fifty- to 54-year-olds were 3.4- and 1.8-fold more likely than were women age 65 or older to be nonadherent to diabetes drugs and statins, respectively, while breast cancer survivors under age 50 were 7.1- and 2.8-fold more likely to be nonadherent to those types of medications.
Discussant Dawn L. Hershman called the COMBO study medication nonadherence rates “pretty awful.” And if breast cancer survivors aren’t taking their medications for chronic comorbid conditions, it’s not much of a leap to think they may not be adherent to their breast cancer–related medications, she said. She urged her fellow breast cancer specialists to think beyond their specialty focus, consider the patient as a whole, and do what they can to promote adherence to medications targeting these potentially serious comorbidities.
“So, what can we do? We can try to engage technology,” said Dr. Hershman, a medical oncologist at Columbia University, New York.
She cited a randomized, controlled trial by other investigators which showed that automated phone calls reminding patients to take their cardiovascular medications had a salutary effect. In addition, she was an investigator in a large study of text messaging as an effective tool for improving adherence to hormonal therapy.
The COMBO study was supported by the National Cancer Institute and the University of Washington, Seattle. Dr. Calip reported having no financial conflicts.