Predictive value of respiratory symptoms and bronchial hyperresponsiveness to diagnose asthma in New Zealand

SummaryRespiratory symptoms are often used as the only diagnostic criteria for asthma in epidemiological surveys and the clinical diagnosis of asthma relies primarily on a detailed history. The aim of this study is to predict the diagnostic value of 11 different respiratory symptoms to diagnose asthma, and to determine if bronchial hyperresponsiveness (BHR) improves the predictive value of these respiratory symptoms.A random sample of 1257 subjects aged 20–44 years old in 3 different areas of New Zealand were selected between March 1991 and December 1992 to answer the European Community Respiratory Health Survey questionnaire on respiratory symptoms. Of these, 784 underwent bronchial challenge with methacholine. The prevalence of current doctor diagnosed asthma (DDA) defined as asthma confirmed by a physician and an asthma attack in the last 12 months was 8.3%. Wheezing with dyspnoea is the single best predictor of diagnosed asthma with a sensitivity of 82%, a specificity of 90% and a Youden's index of 0.72. Wheezing alone is more sensitive (94%) but less specific (76%), with a Youden's index of 0.70. The addition of BHR to asthma symptoms decreases sensitivity and increases specificity with a small increase in Youden's index to 0.75. In New Zealand adults, a history of wheezing with BHR best predicts a diagnosis of asthma but wheezing alone or with dyspnoea are the two best symptoms for predicting asthma

Prevalence of gastro-oesophageal reflux disease symptoms and reflux-associated respiratory symptoms in asthma

<p>Abstract</p> <p>Background</p> <p>Gastro-oesophageal reflux disease (GORD) symptoms are common in asthma and have been extensively studied, but less so in the Asian continent. Reflux-associated respiratory symptoms (RARS) have, in contrast, been little-studied globally. We report the prevalence of GORD symptoms and RARS in adult asthmatics, and their association with asthma severity and medication use.</p> <p>Methods</p> <p>A cross-sectional analytical study. A validated interviewer-administered GORD scale was used to assess frequency and severity of seven GORD symptoms. Subjects were consecutive asthmatics attending medical clinics. Controls were matched subjects without respiratory symptoms.</p> <p>Results</p> <p>The mean (SD) composite GORD symptom score of asthmatics was significantly higher than controls (21.8 (17.2) versus 12.0 (7.6); <it>P </it>< 0.001) as was frequency of each symptom and RARS. Prevalence of GORD symptoms in asthmatics was 59.4% (95% CI, 59.1%-59.6%) versus 28.5% in controls (95% CI, 29.0% - 29.4%). 36% of asthmatics experienced respiratory symptoms in association with both typical and atypical GORD symptoms, compared to 10% of controls (<it>P </it>< 0.001). An asthmatic had a 3.5 times higher risk of experiencing a GORD symptom after adjusting for confounders (OR 3.5; 95% CI 2.5-5.3). Severity of asthma had a strong dose-response relationship with GORD symptoms. Asthma medication use did not significantly influence the presence of GORD symptoms.</p> <p>Conclusions</p> <p>GORD symptoms and RARS were more prevalent in a cohort of Sri Lankan adult asthmatics compared to non-asthmatics. Increased prevalence of RARS is associated with both typical and atypical symptoms of GORD. Asthma disease and its severity, but not asthma medication, appear to influence presence of GORD symptoms.</p

Prevalence of asthma symptoms based on the European Community Respiratory Health Survey questionnaire and FENO in university students: gender differences in symptoms and FENO

<p>Abstract</p> <p>Background</p> <p>The fractional concentration of nitric oxide in exhaled air (F<smcaps>E</smcaps>NO) is used as a biomarker of eosinophilic airway inflammation. F<smcaps>E</smcaps>NO is increased in patients with asthma. The relationship between subjective asthma symptoms and airway inflammation is an important issue. We expected that the subjective asthma symptoms in women might be different from those in men. Therefore, we investigated the gender differences of asthma symptoms and F<smcaps>E</smcaps>NO in a survey of asthma prevalence in university students.</p> <p>Methods</p> <p>The information about asthma symptoms was obtained from answers to the European Community Respiratory Health Survey (ECRHS) questionnaire, and F<smcaps>E</smcaps>NO was measured by an offline method in 640 students who were informed of this study and consented to participate.</p> <p>Results</p> <p>The prevalence of asthma symptoms on the basis of data obtained from 584 students (266 men and 318 women), ranging in age from 18 to 24 years, was analyzed. Wheeze, chest tightness, an attack of shortness of breath, or an attack of cough within the last year was observed in 13.2% of 584 students. When 38.0 ppb was used as the cut-off value of F<smcaps>E</smcaps>NO to make the diagnosis of asthma, the sensitivity was 86.8% and the specificity was 74.0%. F<smcaps>E</smcaps>NO was ≥ 38.0 ppb in 32.7% of students. F<smcaps>E</smcaps>NO was higher in men than in women. The prevalence of asthma symptoms estimated by considering F<smcaps>E</smcaps>NO was 7.2%; the prevalence was greater in men (9.4%) than women (5.3%). A F<smcaps>E</smcaps>NO ≥ 38.0 ppb was common in students who reported wheeze, but not in students, especially women, who reported cough attacks.</p> <p>Conclusions</p> <p>The prevalence of asthma symptoms in university students age 18 to 24 years in Japan was estimated to be 7.2% on the basis of F<smcaps>E</smcaps>NO levels as well as subjective symptoms. Gender differences were observed in both F<smcaps>E</smcaps>NO levels and asthma symptoms reflecting the presence of eosinophilic airway inflammation.</p> <p>Trial registration number</p> <p>UMIN000003244</p

Early detection and counselling intervention of asthma symptoms in preschool children: study design of a cluster randomised controlled trial

Background. Prevention of childhood asthma is an important public health objective. This study evaluates the effectiveness of early detection of preschool children with asthma symptoms, followed by a counselling intervention at preventive child health centres. Early detection and counselling is expected to reduce the prevalence of asthma symptoms and improve health-related quality of life at age 6 years. Methods/design. This cluster randomised controlled trial was embedded within the Rotterdam population-based prospective cohort study Generation R in which 7893 children (born between April 2002 and January 2006) participated in the postnatal phase. Sixteen child health centres are involved, randomised into 8 intervention and 8 control centres. Since June 2005, an early detection tool has been applied at age 14, 24, 36 and 45 months at the intervention centres. Children who met the intervention criteria received counselling intervention (personal advice to parents to prevent smoke exposure of the child, and/or referral to the general practitioner or asthma nurse). The primary outcome was asthma diagnosis at age 6 years. Secondary outcomes included frequency and severity of asthma symptoms, health-related quality of life, fractional exhaled nitric oxide and airway resistance at age 6 years. Analysis was according to the intention-to-treat principle. Data collection will be completed end 2011. Discussion. This study among preschool children provides insight into the effectiveness of early detection of asthma symptoms followed by a counselling intervention at preventive child health centres. Trial registration. Current Controlled Trials ISRCTN15790308

The role of Probiotics in allergic diseases

Allergic disorders are very common in the pediatric age group. While the exact etiology is unclear, evidence is mounting to incriminate environmental factors and an aberrant gut microbiota with a shift of the Th1/Th2 balance towards a Th2 response. Probiotics have been shown to modulate the immune system back to a Th1 response. Several in vitro studies suggest a role for probiotics in treating allergic disorders. Human trials demonstrate a limited benefit for the use of probiotics in atopic dermatitis in a preventive as well as a therapeutic capacity. Data supporting their use in allergic rhinitis are less robust. Currently, there is no role for probiotic therapy in the treatment of bronchial asthma. Future studies will be critical in determining the exact role of probiotics in allergic disorders

Clinical diagnosis of current asthma: predictive value of respiratory symptoms in the SAPALDIA study. Swiss Study on Air Pollution and Lung Diseases in Adults

Bronchial asthma is a very common disease which often remains underdiagnosed. The aim of this study was to determine the predictive value of the most common respiratory symptoms and to explore the best symptom combinations to predict diagnosis of asthma. A questionnaire comprising common respiratory symptoms was submitted to 9,651 subjects aged 18-60 yrs, randomly selected from the Swiss population, of whom 225 subjects (2.3%) had current asthma as confirmed by their general practitioner. Based on these data the authors calculated the predictive values of single symptoms and symptom combinations to diagnose asthma. Wheezing was the most sensitive single symptom (sensitivity 75%). Simple symptoms such as wheezing with dyspnoea, chronic phlegm or chronic cough had specificity greater than 95%. Wheezing with dyspnoea (WD) or nocturnal dyspnoea (ND) had the best positive predictive value (PPV) as isolated symptoms (24% and 21%, respectively). When combining symptoms, wheezing associated with daily dyspnoea at rest or nocturnal dyspnoea showed the best PPV (42% and 39%, respectively), almost double single symptoms such as WD or ND. Wheezing associated with at least two of the three nocturnal symptoms (nocturnal dyspnoea, nocturnal cough or nocturnal chest tightness) had a sensitivity of 80% to diagnose asthma. In conclusion, respiratory symptoms obtained by medical history are reliable predictors of asthma. The findings suggest that particular combinations of symptoms are clinically useful in the differential diagnosis of asthma