Fendrick and others looked at 21 cases that measured the VBID-style prescription drug plans compared with traditional ones. They looked at the impact of low out-of-pocket costs for patients on their medication adherence, measured by how much of the medication the patient had obtained compared with the duration of the prescription. They also looked at what the studies found about health care spending, use of health care services, and clinical outcomes and quality for patients in VBID plans compared with those with non-VBID plans. All of the studies that examined diabetes drug use showed a significant increase in drug adherence with a VBID design.

In other areas such as blood pressure medications, VBID showed considerable improvement in adherence. Two of the five asthma studies showed an increase in adherence. When total costs were reported, two studies showed decreases in spending; seven studies showed no difference, suggesting that decreased spending elsewhere offset increased spending on drugs.

The report says that in addition to enhanced preventive care coverage for more than 140 million Americans, VBID-style coverage has been implemented for people with chronic conditions by several state-sponsored plans, many private employers and federal programs such as TRICARE and Medicare. Fendrick says, “This common-sense legislation could lower out-of-pocket costs for nearly 20 million Americans with chronic conditions.”