Every year, hundreds of thousands of patients with chronic illnesses are forced to switch from their prescribed treatments to medications their health insurance provider decides it prefers.

Some patients refuse to change medicines every time their insurer shifts coverage. Instead, they pay out-of-pocket and either skip doses or cut pills in half to make their original prescriptions last longer. Coverage changes that compel patients to reduce adherence to medication protocols make treatment less effective and ultimately increase the cost of patient care.