Predictors of asthma relapse in patients who attended an emergency department.

BACKGROUND: Patients with asthma exacerbations and frequent relapses that require admission to the emergency department (ED) often have more severe disease, worse quality of life, and higher use of health care resources. OBJECTIVE: The aim of this study was to identify potential predictors of relapse after patients are treated in an ED for an asthma exacerbation. METHODS: A retrospective, noninterventional cohort study was conducted in adult patients who attended the ED of a tertiary hospital in 2014 for an asthma exacerbation. We analyzed the subpopulation who experienced at least one relapse (returned to the ED < 15 days after the previous event). RESULTS: Fifty-two of 831 patients experienced 66 relapses after going to the ED (mean ± standard deviation [SD] age, 58.5 ± 23.4 years). The average ± SD probability of a relapse was 6 ± 0.8%. The frequency of episodes was higher in May and November. Twenty-four patients had ≥260 blood eosinophils/µL, including 17 who had ≥400 eosinophils/µL. Only 15% of the patients were referred to an asthma specialist at discharge. Factors related to a higher probability of relapse were the following: having multiple visits to the ED in 1 year, uncontrolled asthma, wheezing in the pulmonary auscultation, peripheral eosinophilia with ≥400 eosinophils/ µL, and being discharged in the first visit to the ED (p < 0.01 for all). CONCLUSION: In this population, patients who had multiple ED visits in 1 year, those with uncontrolled asthma, wheezing, ≥400 blood eosinophils/µL, or who had been discharged at the first ED visit are at higher risk of relapse.

Usefulness of exhaled nitric oxide for diagnosing asthma.

RATIONALE: A standard asthma diagnosis is made based on clinical history, reversibility of airway obstruction, and bronchial hyperresponsiveness. Fractional exhaled nitric oxide (FeNO) is a noninvasive airway inflammatory marker that has been suggested as a diagnostic tool for asthma. The aim of this study was to establish a FeNO cut-off value for asthma diagnosis. METHODS: One hundred and fourteen consecutive adult patients (mean age 34 ± 13 years) reporting symptoms consistent with asthma, with normal spirometric parameters and a negative bronchodilator test, were included in the study. All underwent a methacholine challenge test following the five-breath dosimeter protocol. FeNO was measured with a portable device (NioxMino, Aerocrine AB, Sweden) just before the methacholine challenge. The sensitivity, specificity, and diagnostic performance of FeNO measurement were calculated. RESULTS: Thirty-five out of the 114 patients (30.7%) were diagnosed with asthma. A positive methacholine challenge was associated with higher FeNO levels and with lower forced expiratory volume in one second (FEV(1)) at baseline. No correlation was found between methacholine provocative concentration causing a decrease of 20% in FEV(1) (PC(20)) and FeNO levels. A receiver-operating characteristic curve was constructed for FeNO levels (area under the curve [AUC]: 0.762; 95% confidence interval [CI]: 0.667-0.857; p < .001). The FeNO cut-off point with maximal specificity and sensitivity for asthma diagnosis was 40 ppb. CONCLUSIONS: Patients with confirmed asthma showed higher FeNO levels. A cut-off value of 40 ppb was calculated as the most efficient for asthma diagnosis in our population. The use of FeNO measurement may be a helpful tool to rule out a diagnosis of asthma, especially in patients in whom a methacholine challenge is not feasible or available.

Cross-reactivity between Parietaria judaica and Parietaria officinalis in immunotherapy extracts for the treatment of allergy to Parietaria.

Parietaria judaica and P. officinalis are the two most common subspecies of the Parietaria genus. P. judaica and P. officinalis have exhibited cross-reactivity in previous studies. P. judaica pollen is the main cause of allergy in the Mediterranean area. It has been shown that a high percentage of patients sensitized to P. judaica with allergic rhinitis (AR) have an increased risk of developing asthma. The present study aimed to confirm the cross-reactivity between P. judaica and P. officinalis and to evaluate the use of a single P. officinalis extract in patients allergic to both subspecies as a preferable option for the diagnosis and treatment of allergy in a highly pollinated area of the Spanish Mediterranean coast. The present study was a single centre, observational cross-sectional study of adult patients diagnosed with AR and/or bronchial asthma who were sensitized to Parietaria pollen. A total of 24 patients were enrolled in the study and included in the analysis. Allergovit® immunotherapy extracts were selected for the study based on the protein content (P. officinalis pollen extract). The results of an in vitro ELISA revealed that 79.1% (n=19) of the patient sera were reactive to immunotherapy extracts. ELISA inhibition assay of the IgE binding to P. officinalis demonstrated inhibition values >70% in the sera of highly reactive patients, confirming the cross-reactivity between the two Parietaria subspecies. In addition, all patients enrolled in the study exhibited double skin positivity against P. judaica and P. officinalis extracts, as assessed by the skin prick test, further supporting the in vivo reactivity between the two subspecies. The present study demonstrated that P. judaica and P. officinalis pollen extracts were highly cross-reactive, and that a unique P. officinalis pollen extract may be used for the diagnosis and immunotherapy of patients allergic to Parietaria.