Bronchodilator Reversibility in the GAN Severe Asthma Cohort.

BACKGROUND AND OBJECTIVE: Positive bronchodilator reversibility (BDR) is a diagnostic criterion for asthma. However, patients with asthma may exhibit a negative BDR response. Aim: To describe the frequency of positive and Negative BDR response in patients with severe asthma and study associations with phenotypic characteristics. METHODS: A positive BDR response was defined as an increase in FEV1 >200 mL and >12% upon testing with a short-acting ß-agonist. RESULTS: BDR data were available for 793 of the 2013 patients included in the German Asthma Net (GAN) severe asthma registry. Of these, 250 (31.5%) had a positive BDR response and 543 (68.5%) a egative BDR response. Comorbidities significantly associated with a negative response were gastroesophageal reflux disease (GERD) (28.0% vs 40.0%, P<.01) and eosinophilic granulomatosis with polyangiitis (0.4% vs 3.0%; P<.05), while smoking history (active: 2.8% vs 2.2%; ex: 40.0% vs 41.7%) and comorbid chronic obstructive pulmonary disease (COPD) (5.2% vs 7.2%) were similar in both groups. Patients with a positive BDR response had worse asthma control (median Asthma Control Questionnaire 5 score, 3.4 vs 3.0, P<.05), more frequently reported dyspnea at rest (26.8% vs 16.4%, P<.001) and chest tightness (36.4% vs 26.2%, P<.001), and had more severe airway obstruction at baseline (FEV1% predicted, 56 vs 64, P<.001) and higher fractional exhaled nitric oxide (FeNO) levels (41 vs 33 ppb, P<0.05). There were no differences in diffusion capacity of the lung for carbon monoxide, single breath (% pred, 70% vs 71%). Multivariate linear regression analysis identified an association between positive BDR response and lower baseline FEV1% (P<.001) and chest tightness (P<.05) and a negative association between BDR and GERD (P<.05). CONCLUSION: In this real-life setting, most patients with severe asthma had a negative BDR response. Interestingly, this was not associated with smoking history or COPD, but with lower FeNO and presence of GERD.

Bronchodilator Reversibility in the GAN Severe Asthma Cohort

Background: Positive bronchodilator reversibility (BDR) is a diagnostic criterion for asthma. However, patients with asthma may exhibit a negative BDR response. Aim: To describe the frequency of positive and negative BDR response in patients with severe asthma and study associations with phenotypic characteristics. Methods: A positive BDR response was defined as an increase in FEV1 >200 mL and >12% upon testing with a short-acting ß-agonist. Results: BDR data were available for 793 of the 2013 patients included in the German Asthma Net (GAN) severe asthma registry. Of these, 250 (31.5%) had a positive BDR response and 543 (68.5%) a negative BDR response. Comorbidities significantly associated with a negative response were gastroesophageal reflux disease (GERD) (28.0% vs 40.0%, P<.01) and eosinophilic granulomatosis with polyangiitis (0.4% vs 3.0%; P<.05), while smoking history (active: 2.8% vs 2.2%; ex: 40.0% vs 41.7%) and comorbid chronic obstructive pulmonary disease (COPD) (5.2% vs 7.2%) were similar in both groups. Patients with a positive BDR response had worse asthma control (median Asthma Control Questionnaire 5 score, 3.4 vs 3.0, P<.05), more frequently reported dyspnea at rest (26.8% vs 16.4%, P<.001) and chest tightness (36.4% vs 26.2%, P<.001), and had more severe airway obstruction at baseline (FEV1% predicted, 56 vs 64, P<.001) and higher fractional exhaled nitric oxide (FeNO) levels (41 vs 33 ppb, P<0.05). There were no differences in diffusion capacity of the lung for carbon monoxide, single breath (% pred, 70% vs 71%). Multivariate linear regression analysis identified an association between positive BDR response and lower baseline FEV1% (P<.001) and chest tightness (P<.05) and a negative association between BDR and GERD (P<.05). Conclusion: In this real-life setting, most patients with severe asthma had a negative BDR response. Interestingly, this was not associated with smoking history or COPD, but with lower FeNO and presence of GERD. (AU)

Antecedentes: La reversibilidad broncodilatadora (RB) positiva es un criterio diagnóstico para el asma. Sin embargo, los pacientes con asma pueden presentar una prueba RB negativa. Objetivos: Describir la frecuencia de RB positivas y negativas en pacientes con asma grave y sus asociaciones con características fenotípicas. Métodos: La RB positiva se definió como un aumento del FEV1 > 200 ml y > 12% tras la inhalación de un agonista beta de acción corta (SABA). Resultados: De 2013 pacientes incluidos en el registro de asma grave del German Asthma Net (GAN), 793 tenían datos sobre RB. De estos, 250 (31,5%) tuvieron una prueba RB positiva y 543 (68,5%) negativa. Las comorbilidades significativamente asociadas con RB negativa fueron el reflujo gastroesofágico (ERGE) (28,0% frente a 40,0%, p<0,01) y EGPA (0,4% frente a 3,0%; p<0,05), mientras que el antecedente de tabaquismo (activo: 2,8% frente a 2,2%; exfumador: 40,0% vs. 41,7%) y la comorbilidad de la EPOC (5,2% vs. 7,2%) fueron similares en ambos grupos. Los pacientes con RB positiva tenían peor control del asma (mediana ACQ-5 3,4 vs. 3,0, p<0,05), más disnea en reposo (26,8% vs. 16,4%, p<0,001) y mayor opresión torácica (36,4% vs. 26,2%, p<0,001), además presentaban una obstrucción de las vías respiratorias más grave al inicio del estudio (FEV1% pred: 56 frente a 64, p<0,001) y niveles más altos de FeNO (41 frente a 33 ppb, p<0,05), mientras que la capacidad de difusión fue similar (DLCO-SB% pred. 70% vs. 71%). El análisis de regresión lineal multivariable identificó una asociación de FEV1% basal inferior (p<0,001) y opresión torácica (p<0,05) con RB positiva y ERGE (p<0,05) con RB negativa. Conclusión: En este entorno en vida real, la mayoría de los pacientes con asma grave tuvieron una RB negativa. Curiosamente, esto no se asoció con antecedentes de tabaquismo o EPOC, sino con FeNO más bajo y presencia de ERGE. (AU)

Identification of a plasma miRNA biomarker signature for allergic asthma: A translational approach.

BACKGROUND: Asthma is a heterogeneous chronic disease with different phenotypes and treatment responses. Thus, there is a high clinical need for molecular disease biomarkers to aid in differentiating these distinct phenotypes. As MicroRNAs (miRNAs), that regulate gene expression at the post-transcriptional level, are altered in experimental and human asthma, circulating miRNAs are attractive candidates for the identification of novel biomarkers. This study aimed to identify plasmatic miRNA-based biomarkers of asthma, through a translational approach. METHODS: We prescreened miRNAs in plasma samples from two different murine models of experimental asthma (ovalbumin and house dust mite); miRNAs deregulated in both models were further tested in a human training cohort of 20 asthma patients and 9 healthy controls. Candidate miRNAs were then validated in a second, independent group of 26 asthma patients and 12 healthy controls. RESULTS: Ten miRNA ratios consisting of 13 miRNAs were differentially regulated in both murine models. Measuring these miRNAs in the training cohort identified a biomarker signature consisting of five miRNA ratios (7 miRNAs). This signature showed a good sensitivity and specificity in the test cohort with an area under the receiver operating characteristic curve (AUC) of 0.92. Correlation of miRNA ratios with clinical characteristics further revealed associations with FVC % predicted, and oral corticosteroid or antileukotriene use. CONCLUSION: Distinct plasma miRNAs are differentially regulated both in murine and in human allergic asthma and were associated with clinical characteristics of patients. Thus, we suggest that miRNA levels in plasma might have future potential to subphenotype patients with asthma.