President Biden and lawmakers in both parties recently laid out proposals to slash Americans' out-of-pocket spending on insulin, which millions of patients -- especially seniors -- rely on to manage their diabetes. Diabetes affects about one in four U.S. adults over 65, and access to insulin is a matter of life and death for many of those patients. So, these proposals could offer literally lifesaving relief to many Americans.

These cost-reduction measures for insulin are immensely promising. But they raise a key question: Why limit the co-pay price caps to just insulin? Six in 10 U.S. adults live with at least one chronic condition and four in 10 are living with two or more. For seniors on Medicare, chronic disease prevalence is even higher and, for millions with fixed incomes, out-of-pocket costs are increasingly problematic.

If the proposed $35-a-month co-pay cap makes sense for insulin — and it does — why not implement the same policies for medicines that treat asthma, hypertension, and other common chronic conditions and focus on Medicare where chronic diseases are so prevalent?

Too many seniors struggle to afford the medications they need to stay healthy. Among Americans with a serious health condition, about one in three have trouble paying for their medicines, according to a recent Kaiser Family Foundation survey. Not to mention how such struggles impact adherence to doctor-prescribed courses of treatment, health status, and overall wellbeing. That drives Medicare spending higher and increases the burdens on beneficiaries and their families.

When people deviate from their prescribed medication regimen, the health consequences can prove dire. Drug non-adherence is estimated to cause 125,000 deaths each year in the U.S. and accounts for 10% of all hospitalizations.

Efforts to cap the out-of-pocket cost of insulin at $35 are a step in the right direction. But given the scope of the affordability crisis, limiting these types of measures to a single class of medications aimed at treating a single illness undercuts both the human and economic saving potential. Starting with Medicare, capping out-of-pocket costs for medicines people depend upon to avoid chronic disease development and progression makes sense.

The most direct, and effective, way to help the millions of Medicare beneficiaries living with chronic conditions afford their medicines is to cap the out-of-pocket cost of common chronic disease drugs. Lawmakers could start by implementing a hard co-pay cap on out-of-pocket chronic disease drug costs for Medicare Part D enrollees, as many have proposed.

There are several reasons lawmakers should back this approach. It would save countless lives and also potentially reduce other healthcare expenditures in Medicare, like hospitalizations. By one estimate, medication non-adherence alone costs our health system as much as $289 billion annually. The policy would also give seniors some much-needed and visible financial relief at the pharmacy counter during a period of record-high inflation.

More than half of Americans support making a $35 insulin cap a top priority in a recent Kaiser Family Foundation poll, and a strict limit on the cost of insulin for patients is a commendable start. A more expansive version of this policy to help Medicare beneficiaries is likely to garner even broader support. By offering the same assistance to people with Medicare living with diabetes and other common chronic diseases, lawmakers can save even more lives and give seniors and their families the kind of bold action on prescription drugs they seek.

Michael Mandel, PhD, is Chief Economist and Vice President of the Progressive Policy Institute. Kenneth E. Thorpe, PhD, is a professor of health policy at Emory University and Chair of the Partnership to Fight Chronic Disease.