Most patients stick with at-home FeNO measurement regimen
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Key takeaways:
- The Vivatmo me measures and records fractional exhaled nitric oxide, symptoms and medication use at home.
- 80.7% of physicians said they would use the device again in the future.
Patients with different asthma severity regularly used a home device for measuring fractional exhaled nitric oxide for 12 weeks as part of their asthma management strategies, according to a poster presentation here.
Daily measurements also detected type 2 inflammation at various cutoffs with increased sensitivity compared with single-point measurements in the doctor’s office, Kai-Michael Beeh, MD, medical director, INSAF Respiratory Research Institute, and colleagues wrote in their poster presented at the European Respiratory Society International Congress.
“FeNO is an essential biomarker of asthma; however, due to the inherent variability of the disease, single-point cross-sectional FeNO measurements may not reflect the true inflammatory status,” Beeh told Healio. “We therefore explored the option of home-based FeNO monitoring with a handheld device over 12 weeks.”
Study design, results
The Vivatmo me (Bosch Healthcare Solutions GmbH) works with a mobile app to allow patients with asthma to measure FeNO and record asthma symptoms and medication use. The researchers hypothesized that daily measurements may provide a more accurate picture of inflammation than single-point, cross-sectional data gathered in a clinical setting.
The multinational observational study included 85 adults (median age, 48 years; 57.6% women) aged 18 to 74 years with asthma, including 23 on Global Initiative for Asthma (GINA) step 1, 37 on GINA step 2 or 3, and 25 on GINA step 4 or 5. Also, 71% of the cohort were using inhaled corticosteroids (ICS) as background medication.
During enrollment, patients attended a clinical visit that included spirometry with FEV1, forced vital control (FVC) and Asthma Control Questionnaire (ACQ) assessments. Lung function was lower and ACQ scores were higher among patients on GINA steps 4 and 5, Beeh said as part of his presentation.
Patients then used the Vivatmo me and attended two more clinical visits over the next 12 weeks at home, followed by a final clinical visit with repeated assessments.
The researchers called adherence excellent, with 71% of the patients covering more than 80% of their measurement days, although adherence in the GINA step 4-5 group was slightly lower, Beeh noted during his presentation.
Specifically, 69.6% of the GINA 1 group, 72% of the GINA 2-3 group and 60% of the GINA 4-5 group covered more than 80% of their measurement days.
“The high adherence is encouraging, as it indicates daily FeNO is feasible in a large, unselected asthma population with different demographic features — an indispensable requirement for any clinical conclusions,” Beeh told Healio.
Also, 82.6% of those in the GINA 1 group, 80.6% of those in the GINA 2-3 group and 87.5% of those in the GINA 4-5 group said learning to use the device was easy or very easy.
Similarly, 82.6% of those in GINA 1, 75% of those in GINA 2-3 and 82.6% of those in GINA 4-5 said using the Vivatmo me was easy or very easy.
When physicians were queried, 13% were neutral about the device or said their expectations were somehow fulfilled, and 87% said their expectations were fulfilled or absolutely fulfilled.
Responses included 65.2% of physicians in the GINA 1 group, 50% of those in GINA 2-3, 33.3% of those in GINA 4-5 and 49.4% of physicians overall who said their expectations were absolutely fulfilled.
The researchers also asked physicians to rate if they were willing to use the Vivatmo me with comparable patients in the future on a scale of 0 to 6, with 0 indicating not at all and 6 indicating absolutely.
Responses included 5 or 6 for 80.7% of the physicians overall, 95.7% for those in the GINA 1 group, 80.6% for those in GINA 2-3 and 66.7% for those in GINA 4-5.
Further, the researchers compared the prevalence of type 2 inflammation at different thresholds, including FeNO of 25 ppb or more for GINA 2-5 during treatment and 40 ppb or more for GINA 1 during diagnosis, between office and home measurements.
Based on both office visits, 36.5% of patients were type 2 low with FeNO under 25 ppb, and 63.5% were type 2 high with at least one FeNO measurement of 25 ppb or higher.
Among patients who used ICS treatment, home measurements identified greater percentages with type 2 high, defined as two or more values at or above 25 ppb, than the office measurements, including 83.3% vs. 58.3% in the GINA 2-3 group and 96% vs. 64% in the GINA 4-5 group.
Additionally, the researchers said that the sensitivity to detect type 2 inflammation increased by 1.4 times in GINA steps 2 and 3, 1.5 times in GINA steps 4 and 5, and 5.3 times in GINA step 1 patients.
“The fact that multiple biomarker measurements provide higher sensitivity may not be surprising,” Beeh said. “Nonetheless, the magnitude of diagnostic yield makes the results very significant.”
Conclusions, next steps
Based on these findings, the researchers concluded that daily FeNO measurement via Vivatmo me is feasible with high adherence and no handling issues among patients as well as positive responses from clinicians with sensitivity that exceeds in-office measurements.
“We firmly believe that the Vivatmo device is an important tool to improve overall outcomes in many subjects with chronic asthma,” Beeh said.
The device also could help support reliable asthma diagnoses in milder forms of asthma by demonstrating the presence or absence of airway inflammation at typical FeNO cutoffs, he continued.
“Finally, longitudinal FeNO data will help to inform us if addition of an inflammatory biomarker refines the concept of asthma ‘remission’ in the future,” Beeh said.
It is important for physicians to have a basic understanding of the biomarker, the device and measurement as well as potential confounders before using the Vivatmo, he added.
“Doctors should also have a clear idea of what they are expecting from the device in a certain patient, eg, type 2 phenotyping, diagnostic uncertainty, adequacy of treatment regime, detection of adherence issues, etc,” Beeh said.
Beeh and his colleagues are now working on publications for major respiratory journals.
“There are tons of data to be analyzed, understood and interpreted,” he said. “However, we are also taking these initial encouraging results as inspiration to further engage in the uptake and implementation of FeNO in asthma everyday care.”
For more information:
Kai-Michael Beeh, MD, can be reached at k.beeh@insaf-wi.de.
Perspective
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Elizabeth A. Townsend, MD, PhD
Asthma is a heterogeneous disease that comprises airway hyperreactivity, airway inflammation and airway remodeling. FeNO is measured in exhaled breath and is used as a dynamic and quantitative marker of airway inflammation.
Triggers of airway inflammation upregulate the inducible nitric oxide synthase enzyme in airway epithelium, which leads to increases in measured FeNO. FeNO correlates best with type 2 airway inflammation.
Taken together with assessments of asthma symptoms and pulmonary function tests, FeNO is an additional tool to help characterize asthma in children and adults. It can be used to assess response to therapy, guide therapy decisions, predict lung function decline, and assess risk for poor asthma control.
However, many factors not related to asthma can also influence FeNO measurements, including age, ethnicity, smoking history, viral respiratory infections, certain foods, and other diseases common in individuals with asthma, including allergic rhinitis and nasal polyps.
This makes it difficult to make decisions based on a single FeNO measurement at an office visit. One could imagine that a diary of daily FeNO readings paired with asthma symptom surveys and peak flow readings could provide a more complete picture of longitudinal asthma control (or loss of control) for an individual.
Daily assessment of asthma — whether through peak flow measurements, daily symptom scores, or now, FeNO measurements — comes with some burden to the individual. This burden increases as individuals feel unwell or experience asthma loss of control. This is reflected in the findings with individuals in GINA steps 4-5 having the lowest adherence to daily FeNO measurements, although adherence was still good overall.
Furthermore, the increase in individuals meeting criteria for type 2 inflammation using serial home measurements reinforces that a single measurement in a clinic may not fully capture an individual’s asthma profile. It may also reflect triggers at home such as pets, smoking or house dust mites that could be modifiable environmental factors.
FeNO measurements are an additional tool to help guide asthma diagnosis and treatment decisions as well as assess response to therapies, but confounders associated with FeNO and its interpretation should be taken in clinical context.
Daily measurements may help demonstrate overall asthma control, impending loss of control or response to changes in treatment when coupled with symptom surveys and peak flow readings, yet clinicians should resist the urge to base asthma treatment decision on any single parameter or measurement given the heterogeneous nature of the disease.
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Beeh KM, et al. Poster 1206. Presented at: European Respiratory Society International Congress; Sept. 7-11, 2024; Vienna.
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