New research was presented at ATS 2020 Virtual, the online annual American Thoracic Society International Conference, from August 5-10. The features below highlight some of the studies presented via the online conference that focus on respiratory disease.
Poverty Affects Respiratory Impacts of Ozone Exposure in COPD
Studies indicate an association between long-term ozone exposure and worse respiratory outcomes in patients with COPD. Although other research suggests that pollutant effects may be greater in low-income communities when compared with other communities, data are lacking on whether ozone effects on respiratory outcomes are greater among smokers living in high poverty neighborhoods. To assess this relationship, researchers examined 1,874 former and current smokers with long-term ozone data and a mean FEV1 percent predicted of 74.7. Statistically significant interactions between neighborhood poverty and increasing ozone concentration were seen with the COPD Assessment Test, modified Medical Research Council dyspnea scale, St. George’s Respiratory Questionnaire, six-minute walk distance, percent air trapping, risk of COPD exacerbation, and risk of severe exacerbation, with adverse effects of ozone greater among those living in high poverty neighborhoods. A 5 ppb increase in ambient ozone concentration was associated with 81% greater odds of COPD exacerbation in the highest poverty neighborhoods (odds ratio [OR], 1.81) but no association in the lowest poverty neighborhoods (OR, 1.09).
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E-Cigarettes Linked With Lower Desire to Quit Smoking Tobacco Cigarettes
As a sub-study to the Take a Break project—funded by the NIH and assessing the abilities of a smoking cessation motivation app—investigators assessed whether tobacco cigarette smokers were more likely to quit if they also smoked e-cigarettes (dual smokers). Among the 405 participants—smokers who were unmotivated to quit—248 were deemed dual smokers after responding “yes” to having ever use e-cigarettes, while 157 were deemed traditional smokers, as they only smoked combustible cigarettes. Dual smokers reported smoking an average of 16 cigarettes per day, compared with 14 per day among traditional smokers. Following a 3-week period of encouraged abstinence from combustible cigarettes, the study team compared participant-reported outcomes. Dual smokers had an average abstinence interval of 0.93 days, compared with 1.8 days for traditional smokers. Dual smokers also reported a harder time quitting completely. A 6-months follow-up, dual smokers smoked a daily average of 12.0 cigarettes, compared with 9.4 for traditional smokers. Reduction in cigarette use from baseline was 21% for dual smokers and 33% for traditional smokers.
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Subphenotypes Don’t Apply to Most COVID-19-Related ARDS
It has been proposed that acute respiratory distress syndrome (ARDS) be subdivided into typical (“H type,” with high elastance, shunt, and lung weight) and atypical (“L type,” with low elastance, shunt, and lung weight) subphenotypes, which might require separate ventilator strategies. To test the hypothesis that patients with low elastance, or high respiratory system compliance (Crs), would also show little consolidation on chest CT scans and that those with high elastance, or low Crs, would show considerable consolidation, researchers analyzed the chest CT scan images of 38 patients with COVID-19 who had been admitted to their ICU. No relationship was observed between Crs and poorly or non-aerated lung tissue. Most patients had nonfocal lung morphology, including more parenchymal involvement but not a lower Crs, when compared with those who had focal lung morphology. Thus, most could not be classified as either H or L subphenotype but instead as showing mixed features.
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More Harm than Good With Antibiotics for Suspected Sepsis?
In an effort to better understand the impact of antibiotic timing on patients suspected of having sepsis with varying risks for death and infection, study investigators examined the data of more than 58,000 adults admitted through the emergency department with suspected infection within 6 hours of arrival and two or more sequential organ failure assessment points within 24 hours of suspected infection. Using deciles of predicted mortality and predicted infection, the study team divided patients into 100 mutually exclusive groups, among whom the likelihood of antibiotic administration within 3 hours of suspected infection was determined for each. Early antibiotic administration was associated with higher mortality among those with 10% predicted mortality and 20% predicted infection. However, a trend toward lower mortality was observed in those with a 10% predicted mortality and 60% predicted infection. The findings argue in favor of giving critical care clinicians more discretion in determining whether to treat suspected sepsis cases with antibiotics than allowed under current guidelines, concluded the presenting study author.
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“Treatable Traits” Approach Valuable for Uncontrolled Asthma
A “treatable traits” approach—with which patients are classified and treated based on the presence or potentially modifiable disease characteristics—has been proposed in the treatment of patients with asthma. For a secondary analysis of the CAPTAIN trial, researchers assessed the value of evaluating eosinophil count and fractional exhaled nitric oxide (FeNO) levels—two key type 2 inflammation biomarkers—in assessing a doubling of patients’ inhaled corticosteroid (ICS) dosage from 100 to 200 μg and the addition of the long-acting antimuscarinic agent in patients with uncontrolled asthma despite dual treatment with the ICS and a long-acting β-2-agonist. The effect of increasing the ICS dose for improving lung function and reducing exacerbations was greater with increasing eosinophil count and FeNO levels. While the proportion of patients with a severe exacerbation on 100 μg of the ICS was nearly three times higher in the high versus low combined type 2 biomarker groups, this disparity was not observed in those treated with 200 μg of the ICS. Benefits of increasing the ICS dose rose with increasing levels of the biomarkers, with no apparent differences in treatment safety.
