Impact of choice of inhalers for asthma care on global carbon footprint and societal costs: a long-term economic evaluation

BACKGROUND

While effective asthma control medications reduce the burden of asthma, a significant subgroup of these treatments, namely metered-dose inhalers (MDIs), produce substantial greenhouse gas (GHG) emissions, thus contributing to climate change. This study quantified the global climate impact (i.e. carbon dioxide equivalent [CO₂e] emissions) and costs of long-term status quo asthma inhaler use versus alternative scenarios substituting MDIs with propellant-free dry powder inhalers (DPIs).

METHODS

Three scenarios were evaluated across 10-year (2020-2030) and 50-year (2020-2070) time horizons: A (status quo inhaler use), B and C (2% and 5% year-over-year substitution of MDIs with DPIs, respectively). Global inhaler volumes and costs at baseline were sourced from IQVIA, then projected using UN and WHO trends in per capita GDP, urbanization, and asthma population growth. Inhaler spending was assumed to fall by 90% following generic entry in 2030. The carbon footprint per inhaler and health damage factors for disability-adjusted life years (DALYs) were derived from literature. The US government's central and high-impact estimates for the social cost of carbon (SCC) were used to calculate emissions costs.

RESULTS

Over 50 years, scenario A resulted in 826 million tonnes of CO₂e emissions globally, with an associated SCC between 21% and 65% of the projected global spending on asthma inhalers. In comparison, CO₂e emissions were reduced by 38% and 58% in Scenarios B and C, respectively, and DALYs improved by 33 and 51%. Depending on SCC estimates, Scenarios B and C increased global costs by 7.3% and 16.5%, respectively (central SCC), or decreased costs by 4.2% and 2.6% (high-impact SCC) versus Scenario A. Over 10 years, Scenario A resulted in 97 million tonnes of CO₂e emissions globally, with an associated SCC between 4.4% and 12.2% of projected spending. In comparison, Scenarios B and C were associated with 12% and 24% reductions in CO₂e emissions and improvements in DALYs by 11.5% and 22.7%, respectively.

CONCLUSIONS

Global efforts by environmental and health-policy decision-makers to substitute currently available MDIs with DPIs for asthma control would result in substantial reductions in GHG emissions with manageable costs, or potential cost savings, depending on the SCC. Policies that decrease use of MDIs warrant global attention.

Carbon footprint and associated costs of asthma exacerbation care among UK adults

INTRODUCTION

Asthma exacerbations are a primary driver of costs and health impacts from asthma. Despite research suggesting that asthma care has a disproportionate carbon footprint, emissions costs are not considered when evaluating its societal burden. To advance the understanding of greenhouse gas (GHG) emissions associated with asthma, we estimated the carbon footprint and associated costs of asthma exacerbation care by severity level among UK adults.

METHODS

Guidelines for asthma exacerbation treatment in UK adults were reviewed by severity level: mild, moderate, and severe/life-threatening. Components of care for each severity were evaluated for GHG emission potential and key drivers were identified. Carbon dioxide equivalent (CO₂e) emissions of drivers were sourced from published literature and combined to estimate the carbon footprint per exacerbation, by severity level. Emissions were scaled up to the annual UK adult population based on the annual number of exacerbations at each severity. Costs associated with emissions were estimated using the UK government's 2020 nontraded price of carbon, at ₤71 per tonne CO₂e (tCO₂e).

RESULTS

Overall, emissions drivers for exacerbations were medical services, including patient-travel, and quick-relief inhalers. The annual number of mild, moderate, and severe/life-threatening asthma exacerbations among UK adults were 118.9 M, 5.5 M, and 2.4 M. Associated annual carbon footprints were estimated to be 83,455 tCO₂e, 192,709 tCO₂e, and 448,037 tCO₂e for mild, moderate, and severe/life-threatening exacerbations, respectively, with a total of 724,201 tCO₂e. Total annual emissions costs from exacerbation care were £51.3 M; ₤5.9 M, ₤13.6 M, and ₤31.7 M for mild, moderate, and severe/life-threatening exacerbations, respectively.

CONCLUSION

GHG emissions from asthma exacerbation management were the highest for severe/life-threatening events, followed by moderate exacerbations. Treatment to reduce the severity and occurrence of exacerbations, such as effective, long-term control therapy via lower-emission dry powder inhalers (DPIs), can help mitigate asthma care emissions. For mild exacerbations, the use of DPIs can eliminate associated emissions.

Cost-Effectiveness Analysis of Omalizumab for Severe Allergic Asthma in Japan Using Real-World Evidence

OBJECTIVES

Omalizumab is a recommended add-on therapy for patients with severe allergic asthma who remain uncontrolled despite treatment with standard of care (SoC). This study evaluated the cost-effectiveness of omalizumab compared with SoC applying real-world clinical outcomes in adult patients with severe allergic asthma in Japan.

METHODS

A validated Markov model was adapted for Japan and compared the cost-effectiveness of omalizumab as an add-on therapy to SoC versus SoC alone using the most recently updated price of omalizumab. A Japanese real-world postmarketing surveillance and a pivotal randomized clinical trial were used as inputs for clinical effectiveness. Japanese life tables and literature were accessed for mortality data and unit costs were extracted from a Japanese insurance claims database. Quality of life data were retrieved from the clinical trial.

RESULTS

In the base case, the incremental cost-effectiveness ratio for omalizumab add-on therapy was ¥2.85 million per quality-adjusted life-year gained (approximately €21 000; 1€ = ¥133.26) compared with SoC alone. The model appeared to be most sensitive to changes in clinically significant severe exacerbation fatality, day-to-day asthma symptom utilities for SoC, discount rates for benefits, day-to-day asthma symptom utilities for omalizumab responders, time horizon, and the annual cost of omalizumab. The results of the probabilistic sensitivity analysis showed that the probability of omalizumab being cost-effective was 93% to 98% at a threshold of ¥5 to ¥6 million (willingness-to-pay for 1 quality-adjusted life-year).

CONCLUSIONS

Omalizumab add-on therapy is cost-effective compared with SoC alone in Japan in severe allergic asthma population who are uncontrolled with high-dose inhaled corticosteroid and other controllers.

A study of as-grown, poled and reduced Rh-doped KNbO3 single crystals by high-resolution X-ray diffraction, Raman scattering, photoluminescence and dielectric measurements

As-grown and chemically reduced Rh-doped (1500 p.p.m.) KnbO3 single crystals grown by the Czochralski method have been characterized. Reduction of the grown crystals at different levels was carried out under a mixture of CO and CO2 gases as the crystals were grown with excess oxygen. The effect of reduction and poling on crystalline perfection was studied by high-resolution X-ray diffraction (HRXRD) using a multi-crystal X-ray diffractometer developed in-house. The diffraction curves of the as-grown, electrically poled, moderately reduced and heavily reduced single-crystal specimens show remarkable differences. The studies by HRXRD reveal that poling has some influence on the improvement of crystalline perfection, while chemical reduction has a great influence on crystalline perfection; at moderate reduction the crystal becomes nearly perfect, but when the reduction is very heavy the crystal quality decreases slightly, although it is still better than for unreduced samples. Asymmetry of the diffraction curves with respect to the peak position reveals that the as-grown specimens contain a high concentration of both vacancies and self-interstitials. After poling, the concentration of self-interstitial defects is lowered to some extent. When the specimen is moderately chemically reduced, the scattered intensity on both sides of the peak is greatly reduced, showing that the concentrations of both vacancies and interstitials are reduced to a great extent owing to chemical reduction. This clearly indicates that, as a result of the chemical reduction of oxygen in the crystal, crystalline perfection is enhanced significantly. However, under heavy chemical reduction, the number of vacancy defects is increased to a significant extent. Raman scattering, dielectric and photoluminescence studies also show interesting features, with excellent correlation with the degree of crystalline perfection influenced by the processes of reduction and poling.

Structure and dynamics of shock-induced nanobubble collapse in water

Shock-induced collapse of nanobubbles in water is investigated with molecular dynamics simulations based on a reactive force field. We observe a focused jet at the onset of bubble shrinkage and a secondary shock wave upon bubble collapse. The jet length scales linearly with the nanobubble radius, as observed in experiments on micron-to-millimeter size bubbles. Shock induces dramatic structural changes, including an ice-VII-like structural motif at a particle velocity of 1  km/s. The incipient ice VII formation and the calculated Hugoniot curve are in good agreement with experimental results.

Study of effect of thermal annealing on crystalline perfection of bismuth germanate single crystals grown by low thermal gradient Czochralski method

Bismuth germanate single crystals containing low angle and very low angle boundaries were selected as specimen for annealing experiments at 1000 °C for varying lengths of time in the range: 8 h to 80 h. Specimen with larger surface along (111) and (100) planes were investigated. The tilt angles of the boundaries were found to be in the range: 16 arc sec to 88 arc sec. Half widths of the diffraction curves of different subgrains were in the range: 15 arc sec to 39 arc sec. High resolution X-ray diffractometry and topography were employed for structural characterization and secondary ion mass spectrometry (SIMS) was used for study of impurity distribution. Annealing led to significant improvement in the crystalline perfection of specimen and all but one of the boundaries could be removed. The very low angle boundaries, which could not be annealed out, had a tilt angle of 41 arc sec. The half widths of diffraction curves of the two remaining subgrains were: 10 arc sec and 17 arc sec. The growth of subgrains as a result of annealing was investigated. SIMS investigation of annealed specimen, in which a very low angle boundary persisted, showed the boundary was decorated with silicon impurity, which presumably acted as a pining center. Detailed diffractometric and topographic experiments helped in delineating the two subgrains around the very low angle boundary. The morphological features of the very low angle boundary were studied in detail.

Study of point defects in as-grown and annealed bismuth germanate single crystals

Point defects and their clusters in bismuth germanate single crystals free from grain boundaries and having low density of dislocations were studied by high-resolution diffuse X-ray scattering measurements. Differences in defects in the colourless crystals (type A) and the crystals having yellow tinge (type B), which were grown with different raw materials, were investigated. In addition, interesting differences in defect structures in specimens from different regions of the same boule were investigated. Specimens with diffracting surfaces along (111), (112) and (100) planes were studied. A multicrystal X-ray diffractometer employing a well collimated and highly monochromated Mo Kα1 beam and set in (+,−,−,+) configuration was employed. The diffraction curves of all the samples were quite narrow with half-widths in the range 7–11 arcsec, which are close to the theoretically expected values, if instrumental broadenings are taken into account. The observed distribution of diffuse X-ray scattering (DXS) intensity showed that not all the point defects are isolated but a significant fraction are agglomerated into clusters. Experimental data of DXS intensity were analysed by using a phenomenological model for a small concentration of dislocation loops wherein the point defects are loosely clustered with weak interactions among them. From this analysis, the cluster radius R cl, cluster volume A cl, the number of point defects within a cluster N cl and the relative concentration of the point-defect clusters among the samples were estimated. It was observed that cluster sizes do not vary from sample to sample. However, it was found that the concentration of clusters is approximately twice in the coloured sample compared with that of the colourless sample from the same boule. Annealing of the crystals at 1273 K produced an increase in point-defect clusters by a factor of ∼200. It was accompanied by a reduction in volume of clusters by a factor of ∼0.14.