Daily Respiratory Research Analysis
Three high-impact studies stood out today: a large U.S. cohort showed that completely switching from cigarettes to e‑cigarettes was associated with short‑term improvements in functionally important respiratory symptoms comparable to quitting; a single-center cohort reported high uptake of maternal RSV vaccination and infant nirsevimab with no signal for increased preterm birth; and an international VV‑ECMO registry analysis found a non‑linear association between BMI and mortality, partly mediate
Summary
Three high-impact studies stood out today: a large U.S. cohort showed that completely switching from cigarettes to e‑cigarettes was associated with short‑term improvements in functionally important respiratory symptoms comparable to quitting; a single-center cohort reported high uptake of maternal RSV vaccination and infant nirsevimab with no signal for increased preterm birth; and an international VV‑ECMO registry analysis found a non‑linear association between BMI and mortality, partly mediated by pulmonary complications.
Research Themes
- Harm reduction and respiratory symptom outcomes with e-cigarette switching
- Early implementation and equity of maternal RSV prevention strategies
- Obesity paradox and mechanisms in VV-ECMO outcomes
Selected Articles
1. Functionally important respiratory symptoms and continued cigarette use versus e-cigarette switching: population assessment of tobacco and health study waves 2-6.
In a longitudinal, nationally representative cohort of U.S. adults who smoked, completely switching to e‑cigarettes was associated with lower risk of respiratory symptom worsening (RR 0.69) and higher likelihood of improvement (RR 1.31) versus continued smoking, with magnitudes similar to quitting. Sensitivity analyses supported these findings.
Impact: This study provides policy-relevant, longitudinal evidence that complete switching to e-cigarettes can yield short-term respiratory symptom benefits comparable to quitting, informing harm-reduction strategies for adults unable to stop nicotine use.
Clinical Implications: For adult smokers unwilling or unable to quit, complete switching to e‑cigarettes may reduce functionally important respiratory symptoms relative to continued smoking; clinicians should couple this with cessation support and guard against youth uptake.
Key Findings
- Among baseline low-symptom participants (index <2), symptom worsening occurred in 15.4% (continued smoking), 10.0% (e-cig switch), 10.1% (quit); adjusted RR for worsening: 0.69 (switch) and 0.73 (quit) versus continued smoking.
- Among baseline higher-symptom participants (index ≥2), symptom improvement occurred in 27.7% (continued), 45.8% (switch), 42.1% (quit); adjusted RR for improvement: 1.31 (switch) and 1.36 (quit).
- Findings were directionally consistent using a stricter symptom cutoff (≥3) and in sensitivity analyses including partial follow-up data.
Methodological Strengths
- Nationally representative longitudinal cohort with repeated two-wave observations (2014–2021)
- Multivariable modeling with explicit symptom indices and sensitivity analyses
Limitations
- Observational design with self-reported symptoms and tobacco product use
- Short-term symptom outcomes; no objective lung function or long-term clinical endpoints
Future Directions: Assess long-term respiratory outcomes (lung function, exacerbations) and safety; evaluate subgroups (e.g., asthma/COPD), device types, and dual-use dynamics; incorporate objective biomarkers.
2. Respiratory Syncytial Virus Vaccine and Nirsevimab Uptake Among Pregnant People and Their Neonates.
At a single academic center, 64% of eligible pregnant people received the RSVpreF vaccine and 70% of eligible infants received nirsevimab before discharge, with overall RSV coverage exceeding 80% after the first month. Maternal vaccination was not associated with preterm birth, and uptake disparities by language and race were observed.
Impact: Provides early real-world implementation data for dual maternal–infant RSV prevention with reassuring perinatal safety and highlights equity gaps, informing health systems and public health rollouts.
Clinical Implications: Health systems can expect high uptake of maternal RSVpreF and infant nirsevimab with coordinated programs; targeted outreach is needed for non‑English speakers and marginalized racial groups to close gaps.
Key Findings
- Maternal RSVpreF uptake was 64.0% (414/647); infant nirsevimab uptake was 70.1% (183/261) before discharge.
- RSV coverage exceeded 80% in all months after October 2023; maternal vaccination showed no association with preterm birth (AOR 1.03; 95% CI 0.55–1.93).
- Uptake was higher with older age, nulliparity, private insurance, and prior vaccinations, and lower with non‑English language preference, Black race, other/unknown race, and multiple gestation.
Methodological Strengths
- Clear eligibility windows and multivariable modeling with adjusted odds ratios
- Nested case–control analysis for preterm birth safety signal
Limitations
- Single-center retrospective design limits generalizability; short time window after approval
- Potential supply, access, and policy factors not fully captured
Future Directions: Multicenter evaluations across diverse populations; assess infant clinical outcomes (RSV hospitalizations) and cost‑effectiveness; targeted interventions to reduce disparities.
3. The Association Between Body Mass Index and Mortality Mediated by Medical and Mechanical Complications in Venovenous Extracorporeal Membrane Oxygenation.
In 24,796 VV‑ECMO adult runs, higher BMI was associated with lower hospital mortality in a nonlinear pattern (e.g., OR 0.82 at BMI 40 vs 25). Mediation analyses suggested pulmonary complications partially explained the association, whereas some complications acted as suppressors, refining understanding of the “obesity paradox.”
Impact: This large, contemporary international analysis clarifies BMI–mortality relationships on VV‑ECMO and identifies mediating pathways, informing patient selection and complication mitigation strategies rather than using BMI cutoffs alone.
Clinical Implications: BMI alone should not exclude candidates from VV‑ECMO; anticipate and manage pulmonary complications in higher‑BMI patients to optimize outcomes; consider device and circuit strategies to minimize mechanical complications.
Key Findings
- Nonlinear BMI–mortality association: compared with BMI 25 kg/m², BMI 20 increased death risk (OR 1.11), BMI 30 decreased risk (OR 0.92), BMI 40 decreased risk further (OR 0.82).
- BMI correlated with mechanical, renal, pulmonary, and neurologic complications; pulmonary complications partially mediated the BMI–mortality association.
- Mechanical, renal replacement therapy, and neurologic complications acted as suppressing mediators, indicating complex pathways underlying the observed survival advantage.
Methodological Strengths
- Very large international multicenter registry with contemporary practice (2015–2021)
- Advanced modeling using fractional polynomials and formal mediation analysis
Limitations
- Retrospective registry with potential residual confounding and variable coding across centers
- Causality cannot be established; limited granularity on nutritional status or body composition
Future Directions: Prospective studies to validate mediators; integrative models incorporating body composition, inflammation, and ventilatory strategies; trials of targeted complication prevention in higher‑BMI ECMO patients.