Study Finds Insurance Plans Still Favor High-Emission Asthma Inhalers Over Greener Options

A study published in JAMA Network Open found that commercial insurance plans in the U.S. routinely make it harder for patients to get lower-emission asthma and COPD inhalers than the traditional metered-dose kind.

The research, led by Soko Setoguchi, MD, DrPH, and Ashwaghosha Parthasarathi, MBBS, both of the Rutgers RWJBarnabas Center for Climate, Health, and Healthcare, examined 31,219 commercial plan formularies across all 50 states and Washington, D.C., using data from the MMIT Coverage Search pulled in May 2026.

The numbers are stark. For short-acting beta2-agonists, the rescue inhalers used during asthma attacks, 66.4% of plans covered only a metered-dose version with no propellant-free option available at all, according to the study.

Metered-dose inhalers rely on hydrofluoroalkane propellants, which are greenhouse gases. Dry powder inhalers and soft mist inhalers don't use them, and the researchers say switching more patients to those devices would cut emissions.

For inhaled corticosteroids and combination inhalers, the picture was better but still lopsided. More than 99% of plans covered at least one version of each drug class, but propellant-free options were covered by only 89.5% of plans for inhaled corticosteroids and 82.6% for the combination inhaler-plus-long-acting bronchodilator, per the study.

Setoguchi and Parthasarathi told MedPage Today that availability isn't the issue. Low-emission inhalers are FDA-approved and on the market. The problem, they said, is that insurance formulary design, including prior authorization requirements and step therapy rules, pushes patients toward the higher-emission metered-dose version by default.

"A clinician might identify an environmentally friendly inhaler suitable for their patient, only to discover that the patient's insurance does not cover it or requires extra steps to obtain it," the researchers said.

This follows a prior study from the same team that found similar formulary patterns in Medicare plans. The researchers say inhalers from these three drug classes account for nearly all inhaler-related greenhouse gas emissions in the U.S., which they estimate is roughly equivalent to the emissions from half a million gasoline-powered cars driven for a year.

The Fair Complaint Underneath the Climate Framing

Strip away the emissions math and there's a legitimate access complaint here. If a doctor and patient decide together that a dry powder or soft mist inhaler is the better clinical fit, and the patient is repeatedly bounced back to a step therapy requirement or a prior authorization form before the insurer will cover their actual choice, that's a real friction point in the healthcare system, regardless of anyone's opinion on climate policy.

But the study itself is upfront about what it didn't measure. It looked at formulary structure only, not actual patient enrollment, out-of-pocket costs, coverage exceptions, prescribing patterns, or whether switching devices was clinically appropriate for any given patient, according to the authors' own stated limitations.

Dry powder inhalers require a strong, fast inhalation to work properly, which makes them a poor fit for young children, elderly patients, or anyone in the middle of a severe asthma or COPD flare-up. Metered-dose inhalers paired with a spacer remain the standard choice in those situations for good clinical reasons that have nothing to do with insurer stinginess.

The study also doesn't say whether the lower-emission alternatives cost insurers or patients more. If they do, formulary tiering that favors the cheaper metered-dose option isn't necessarily an environmental failure. It could just be normal insurance math.

A Global Push, Not Just a U.S. Insurance Problem

The formulary gap isn't happening in a vacuum. The International Primary Care Respiratory Group published a Norwegian-language infographic on September 21, 2026, laying out a national timeline for transitioning pressurized metered-dose inhalers to propellants with lower global warming potential, aimed at prescribers and pharmacists.

That reflects a broader regulatory push already underway in parts of Europe, where governments, not just insurers, are pressing manufacturers and health systems to phase down high-GWP propellants. The U.S. study, by contrast, is aimed at private insurance formulary design, not federal mandate, at least for now.

Setoguchi and Parthasarathi's stated goal is "lower formulary barriers for propellant-free options while preserving metered-dose inhaler access when clinically indicated." That's a reasonable ask on its face. Whether insurers respond, or whether state or federal regulators start leaning on formulary design over emissions concerns, is the open question the study doesn't answer. No such regulatory action has been announced as of this writing.