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.

The impact of COPD on polyneuropathy: results from the German COPD cohort COSYCONET

Background

Peripheral neuropathy is a common comorbidity in COPD. We aimed to investigate associations between alterations commonly found in COPD and peripheral neuropathy, with particular emphasize on the distinction between direct and indirect effects.

Methods

We used visit 4 data of the COPD cohort COSYCONET, which included indicators of polyneuropathy (repeated tuning fork and monofilament testing), excluding patients with diabetes a/o increased HbA1c. These indicators were analysed for the association with COPD characteristics, including lung function, blood gases, 6-min walk distance (6-MWD), timed-up-and-go-test (TUG), exacerbation risk according to GOLD, C-reactive protein (CRP), and ankle-brachial index (ABI). Based on the results of conventional regression analyses adjusted for age, BMI, packyears and gender, we utilized structural equation modelling (SEM) to quantify the network of direct and indirect relationships between parameters.

Results

606 patients were eligible for analysis. The indices of polyneuropathy were highly correlated with each other and related to base excess (BE), ABI and TUG. ABI was linked to neuropathy and 6-MWD, exacerbations depended on FEV₁, 6-MWD and CRP. The associations could be summarized into a SEM comprising polyneuropathy as a latent variable (PNP) with three measured indicator variables. Importantly, PNP was directly dependent on ABI and particularly on BE. When also including patients with diabetes and/or elevated values of HbA1c (n = 742) the SEM remained virtually the same.

Conclusion

We identified BE and ABI as major determinants of peripheral neuropathy in patients with COPD. All other associations, particularly those with lung function and physical capacity, were indirect. These findings underline the importance of alterations of the micromilieu in COPD, in particular the degree of metabolic compensation and vascular status.

Home Self-Administration of Biologics - A German Survey among Omalizumab-Treated Patients with Severe Asthma and their Treating Physicians

In the EU, five biologics have been approved as add-on therapy for patients with severe asthma. Until recently, none of the biologics was approved for home use and had to be administered under medical supervision, a time-consuming schedule for both patients and physicians, accompanied by greater expenditure. However, over the last year, four out of the five biologics have been granted approval for patient self-administration at home. The objective of this multiple-choice survey was to understand how patients with severe asthma treated with omalizumab and their treating physicians view the potential home use of biologics exemplified by omalizumab. The questionnaires were answered by 120 physicians and 432 patients (response rate: 51.7 % and 20.6 %, respectively). Overall, 44.7 % of patients were in favour of self-administration at home while 30.6 % opposed this method of administration and 23.8 % of patients were neutral. Especially teenagers and young adults had a positive attitude towards self-administration. 76.7 % of the questioned physicians were in favour of home use for certain patients. Time saving was the main advantage for self-administration mentioned by patients (53.2 %) as well as by physicians (72.5 %). The main concern for patients was 'making a mistake while injecting' (43.8 %) while 'forgetting to inject omalizumab' (73.3 %) was the main concern for physicians. 44.4 % of patients expressed a wish for individual training and 70.8 % of physicians agreed with this statement. The latter group also considered a starter kit including several information materials (54.2 %) as well as an electronic reminder system (50.8 %) as useful. In conclusion, self-administration of biologics has the potential to be timesaving for both patients and physicians.

Structural features of some diphenhydramine analogues that determine the interaction with rat liver cytochrome P-450

The aim of this study was to define the structural characteristics in a series of 21 analogues of the anti-histaminergic drug diphenhydramine which are important for the interaction with cytochrome P-450. The compounds gave substrate (type I) binding spectra with rat hepatic microsomal cytochrome P-450. The main findings were: (1) two phenyl rings are needed for strong binding: saturation or elimination of one ring, or restriction of two phenyls with a two-carbon bridge results in a decrease of binding, (2) substitution on one or both aromatic rings has only a small influence on binding, (3) an amine nitrogen contributes to better binding; decrease or absence of basicity weakens binding, and (4) a chain of 4 to 7 atoms connecting the basic centre with the aromatic part is needed; reduction of the chain length, or restriction of it to a cyclic structure causes decrease or loss of binding ability.