A new paper in NBER looks at the deadly consequences of out-of-pocket costs in the Medicare Part D prescription drug program. As you might expect, deductibles and copays keep people from filling their prescriptions. What you might not expect is that when costs rise on one prescription, people sometimes stop filling all of their prescriptions.

Most people have little ability to rank order the value of their different prescriptions or to prioritize one prescription over another when they cannot afford them all. So, instead, they make random decisions about which ones to stop taking or decide to stop taking all of them. In short, while cost-sharing might reduce overuse of medicines, it also can lead to poor health outcomes and premature deaths.

The researchers found that a $10.40 increase in a drug’s cost leads more than one in five people to stop filling their prescriptions altogether. It also increases the likelihood of people dying.

When out-of-pocket costs rise, people stop taking statins and antihypertensives which can extend their lives significantly. And, people who are most at risk for a heart attack or stroke are likely to reduce their use of these drugs even more than people who are at lower risk. Socioeconomic status apparently has little bearing on people’s behavior.

Most interesting and disturbing, the researchers find that, when drug prices increase, nearly one in five additional people opt not to fill any prescriptions. This reaction apparently holds whether they take one additional medicine or multiple additional medicines. Moreover, the risks of not taking medicines apparently have no bearing on people’s behavior.

The researchers only looked at the effects of drug costs on patient mortality not on morbidity. They conclude that “patient cost-sharing introduces large and deadly distortions into the cost-benefit calculus. Payers should evaluate the merits of these policies in light of their impact on health, not just on health care costs.”

If we value people’s lives and well-being, it’s time to do away with rationing care based on ability to pay.