Women with breast cancer who were previously nonadherent to medications for chronic conditions tended to be the same way with oral hormonal therapy (HT), according to a retrospective cohort study involving more than 21,000 women.

Investigators defined medication nonadherence as a medication possession ratio less than 80%. Among the results:

• ~16% of all patients were nonadherent.
• Patients <55 or ≥75 years of age were more apt to be nonadherent, as were those with higher 30-day, out-of-pocket costs and increased comorbidities.
• Women without prior medications for 1 of the chronic conditions (~4 in every 10) had an 18% nonadherence rate to HT.
• Those who used 1 or more medication prior to HT and were adherent (43%) had a 10% nonadherence rate to HT.
• Those who were nonadherent to their chronic medications (2 in every 10) had a 23% nonadherence rate to HT.