Yes, and no. Within the IMPACT and ETHOS trials, single-inhaler triple therapy did lower all-cause mortality in COPD, and that result survives scrutiny as far as it goes. But the benefit only appears against one particular comparator: a two-drug bronchodilator inhaler with no steroid inside it. Set triple therapy next to a steroid-containing inhaler instead, or study patients who were not on a steroid to begin with, and the survival advantage thins out or disappears. The most defensible reading is that these trials tell us something about inhaled steroids and about how the studies were built, not that a third drug in the canister rescues everyone.
Key points#
- IMPACT and ETHOS both found a mortality signal favoring triple therapy, but only against a no-steroid bronchodilator comparator.
- Against a steroid-containing comparator, the mortality difference was not statistically significant in either trial.
- Most enrollees were already on an inhaled steroid, so the comparator arm had a steroid stopped on day one, which can itself cause harm.
- The useful clinical question is who benefits from an inhaled steroid at all, not whether three drugs beat two.
Start with the question, not the headline#
It helps to reframe what these trials were actually testing. A single-inhaler triple product combines three drug classes: an inhaled corticosteroid, a long-acting muscarinic antagonist, and a long-acting beta agonist. When you compare that against a two-drug inhaler, you are almost never changing just one variable. In these trials the comparator determined whether an inhaled steroid was present or absent, and that turns out to be the hinge the whole mortality story swings on.
The two trials#
IMPACT (Lipson and colleagues, New England Journal of Medicine, 2018) randomized more than 10,000 people with symptomatic COPD and a history of flare-ups. One group received a single inhaler of fluticasone furoate, umeclidinium, and vilanterol. The comparison groups received one of two dual inhalers: fluticasone furoate plus vilanterol (a steroid with a long-acting beta agonist) or umeclidinium plus vilanterol (two bronchodilators, no steroid).
ETHOS (Rabe and colleagues, New England Journal of Medicine, 2020) ran a similar design in roughly 8,500 patients, pairing budesonide, glycopyrrolate, and formoterol against a matched bronchodilator-only inhaler and against a steroid-plus-bronchodilator inhaler. In both trials the primary endpoint was the rate of moderate or severe flare-ups, which triple therapy reduced. The result that made headlines, though, was a secondary one: fewer deaths.
What the death numbers were#
In the IMPACT mortality analysis (Lipson and colleagues, American Journal of Respiratory and Critical Care Medicine, 2020), investigators recovered vital status for 99.6% of participants. About 2.4% of the triple-therapy group died versus about 3.2% of the bronchodilator-only group, a hazard ratio of 0.72 (95% CI 0.53 to 0.99). Against the steroid-containing pair, the hazard ratio was 0.89 (95% CI 0.67 to 1.16), which did not reach significance.
ETHOS made the pattern sharper. In its dedicated mortality analysis (American Journal of Respiratory and Critical Care Medicine, 2021), the higher-dose triple combination cut all-cause mortality against the bronchodilator-only pair with a hazard ratio of 0.51 (95% CI 0.33 to 0.80), close to halving the risk. Against the steroid-containing comparator, the gap was again not significant. In both trials, the mortality benefit lived entirely in the comparison with the arm that carried no inhaled steroid.
The objection that survives#
Two criticisms followed the trials. The first, about missing data, was answered well. Early reports had incomplete vital status, and when a few percent of outcomes are unknown, they can swamp a small mortality difference. Under regulatory pressure, sponsors chased down those outcomes: in ETHOS the share of patients with unknown week-52 vital status dropped from roughly 4.5% to about 0.4% after sites, patients, and death registries were searched. The benefit held. That is a point in the finding's favor, and it is why the signal cannot be dismissed as a bookkeeping artifact.
The second criticism is harder to answer, and it is the one that reframes everything. As Suissa has detailed (CHEST, 2022), roughly 70% to 80% of enrollees across IMPACT and ETHOS were already taking an inhaled steroid when they joined. Anyone randomized to a bronchodilator-only arm therefore had that steroid stopped abruptly on day one. Withdrawing an inhaled steroid from a steroid-dependent patient can provoke early flare-ups, so some deaths in the comparator arm may reflect the harm of a sudden stop rather than any special power of adding two more drugs.
The timing supports that reading. The survival curves separated mostly in the first months, exactly when withdrawal harm would show up, a pattern epidemiologists call depletion of susceptibles. The benefit also concentrated in patients who had been on a steroid before randomization. In the smaller group who were steroid-naive at entry, and who therefore had nothing withdrawn, no clear survival advantage remained and the confidence intervals crossed no difference. If the third drug itself saved lives, the benefit should not track so tightly with whether a steroid had just been taken away.
Why the comparator decides the answer#
Line the results up and they point one way. Against a no-steroid comparator, triple therapy looks life-saving. Against a steroid-containing comparator, the difference is not significant. Among patients never on a steroid to begin with, no clear benefit appears. The constant is the inhaled steroid, not the count of drugs in the device. Part of the apparent gain is a genuine steroid effect in patients who respond to steroids, and part is harm avoided in the comparator arm simply by not stopping a steroid.
That shifts the practical question. The decision worth making is which patients gain from an inhaled steroid at all, rather than whether a three-drug inhaler beats a two-drug one. Higher blood eosinophil counts and a history of frequent flare-ups mark the people most likely to benefit. Inhaled steroids also carry costs of their own, including a raised risk of pneumonia, so the choice is a balance rather than a default. A blanket claim that triple therapy lowers COPD deaths overshoots the evidence. A narrower claim, that adding an inhaled steroid lowers mortality in steroid-responsive patients compared with no steroid at all, sits much closer to what the trials actually show.
Sources and further reading
Questions and answers
So does triple therapy save lives or not?
Inside IMPACT and ETHOS, measured against a bronchodilator inhaler with no steroid, it lowered deaths. As a general promise it is qualified by the comparator, by who was enrolled, and by what was stopped at randomization.
Is the benefit really from the third drug?
Probably not on its own. The signal follows the inhaled steroid and follows whether a steroid was withdrawn from the comparison group, which suggests the steroid, not the number of drugs, is doing the work.
Who is most likely to benefit from an inhaled steroid in COPD?
People with higher blood eosinophil counts and frequent flare-ups tend to respond best. The added pneumonia risk means the decision is individual, and it belongs with a patient and their own clinician. Treatment decisions belong with a patient and their own clinician.