What defines airflow obstruction in asthma?

Asthma guidelines from the Global Initiative for Asthma (GINA) and from the National Heart, Lung, and Blood Institute provide conflicting definitions of airflow obstruction, suggesting a fixed forced expiratory volume in 1 s (FEV(1))/forced vital capacity (FVC) cut-off point and the lower limit of normality (LLN), respectively. The LLN was recommended by the recent American Thoracic Society/European Respiratory Society guidelines on lung function testing. The problem in using fixed cut-off points is that they are set regardless of age and sex in an attempt to simplify diagnosis at the expense of misclassification. The sensitivity and specificity of fixed FEV(1)/FVC ratios of 0.70, 0.75 and 0.80 versus the LLN were evaluated in 815 subjects (aged 20-44 yrs) with a diagnosis of asthma within the framework of the European Community Respiratory Health Survey. In males, the 0.70 ratio showed 76.5% sensitivity and 100.0% specificity, the 0.75 ratio 100.0% sensitivity and 92.4% specificity, and the 0.80 ratio 100.0% sensitivity but 58.1% specificity. In females, the 0.70 ratio showed 57.3% sensitivity and 100.0% specificity, the 0.75 ratio 91.5% sensitivity and 95.9% specificity, and the 0.80 ratio 100.0% sensitivity but 72.9% specificity. The fixed cut-off points cause a lot of misidentification of airflow obstruction in young adults, with overestimation with the 0.80 ratio and underestimation with the 0.70 ratio. In conclusion, the GINA guidelines should change their criteria for defining airflow obstruction.

Underestimation of airflow obstruction among young adults using FEV1/FVC <70% as a fixed cut-off: a longitudinal evaluation of clinical and functional outcomes.

BACKGROUND: Early detection of airflow obstruction is particularly important among young adults because they are more likely to benefit from intervention. Using the forced expiratory volume in 1 s (FEV(1)) to forced vital capacity (FVC) (FEV(1)/FVC) <70% fixed ratio, airflow obstruction may be underdiagnosed. The lower limit of normal (LLN), which is statistically defined by the lower fifth percentile of a reference population, is physiologically appropriate but it still needs a clinical validation. METHODS: To evaluate the characteristics and longitudinal outcomes of subjects misidentified as normal by the fixed ratio with respect to the LLN, 6249 participants (aged 20-44 years) in the European Community Respiratory Health Survey were examined and divided into three groups (absence of airflow obstruction by the LLN and the fixed ratio; presence of airflow obstruction only by the LLN; presence of airflow obstruction by the two criteria) for 1991-1993. LLN equations were obtained from normal non-smoking participants. A set of clinical and functional outcomes was evaluated in 1999-2002. RESULTS: The misidentified subjects were 318 (5.1%); only 45.6% of the subjects with airflow obstruction by the LLN were also identified by the fixed cut-off. At baseline, FEV(1) (107%, 97%, 85%) progressively decreased and bronchial hyperresponsiveness (slope 7.84, 6.32, 5.57) progressively increased across the three groups. During follow-up, misidentified subjects had a significantly higher risk of developing chronic obstructive pulmonary disease and a significantly higher use of health resources (medicines, emergency department visits/hospital admissions) because of breathing problems than subjects without airflow obstruction (p<0.001). CONCLUSIONS: Our findings show the importance of using statistically derived spirometric criteria to identify airflow obstruction.

Chronic productive cough in young adults is very often due to chronic rhino-sinusitis.

BACKGROUND: Chronic productive cough is a common clinical problem; often potential causes outside the lower respiratory tract are forgotten or ignored. The aim of this study was to make a precise etiopathogenetic diagnosis of chronic productive cough in young adults. METHODS: In a clinical setting, 212 subjects (mean age 41+/-5 years) who had reported chronic productive cough in a previous postal survey of a young adult population underwent within two years clinical and functional investigations following a rational diagnostic approach. Two pulmonologists independently established the diagnosis using a clinically structured interview on nasal and respiratory symptoms, spirometry and other tests when appropriate (bronchodilator test or methacholine bronchial challenge, chest radiography); if rhino-sinusitis was suspected, subjects underwent an ENT examination with nasal endoscopy and/or sinus computed tomography. RESULTS: At the end of the diagnostic procedure, 87 subjects (41%) no longer had chronic productive cough and had normal function. Fifty-eight subjects (27%) had chronic rhino-sinusitis; seventeen subjects (8%) had asthma, and of these fourteen also had chronic rhino-sinusitis; 50 subjects (24%) had COPD stage 0+, of these seven also had chronic rhino-sinusitis. Chronic rhino-sinusitis was more frequent in females than in males (p<0.05). CONCLUSIONS: Both in clinical practice and in epidemiological studies, it is important to consider that the origin of chronic productive cough could be frequently outside the lower respiratory tract; a consistent percentage of young adults with persistent productive cough has indeed chronic rhino-sinusitis.

Occupational asthma: a longitudinal study on the clinical and socioeconomic outcome after diagnosis.

AIM: To evaluate the clinical outcome and socioeconomic consequences of occupational asthma (OA). SUBJECTS AND METHODS: Twenty-five patients with OA both to high- and low-molecular-weight agents (3 and 22, respectively) confirmed by specific inhalation challenge were followed up for 12 months after the diagnosis. Upon diagnosis, each patient received a diary on which to report peak expiratory flow rate (PEFR), symptoms, drug consumption, expenses directly or indirectly related to the disease, as well as information regarding personal socioeconomic status. At each follow-up visit (1, 3, 6, and 12 months), the patients underwent clinical examination, spirometry, methacholine (Mch) challenge, and assessment of diary-derived parameters and socioeconomic status. Asthma severity (AS) was classified into four levels, based on symptoms, drug consumption, and PEFR variability. RESULTS: At 12 months, 13 patients (group A) had ceased exposure; the remaining 12 patients (group B) continued to be exposed. At diagnosis, FEV1 percent and provocative dose causing a 20% fall in FEV1 (PD20) of Mch were lower in group A than in group B; patients of group A were also characterized by significantly higher basal AS levels. At 12 months, no significant variation in FEV1 percent or PD20 was found for either group, while AS levels improved in both groups, the change being more marked for group A than group B. Pharmaceutical expense at 12 months significantly (p < 0.05) decreased, as compared with the first month, in group A, whereas it tended to increase in group B. In group A, 9 of 13 subjects had reported a deterioration of their socioeconomic status as compared with 2 of 12 in group B (p < 0.01). A significant loss of income was registered in patients of group A (median 21.45, 25th to 75th percentiles 16.9 to 25.8 Italian liras x 10(6) on the year preceding diagnosis and 15.498, 10.65 to 21.087 Italian liras x 10(6) on the year after diagnosis; p < 0.01), whereas no significant change was seen for patients in group B. CONCLUSIONS: In OA, cessation of exposure to the offending agent results in a decrease in asthma severity and in pharmaceutical expenses, but it is associated with a deterioration of the individual's socioeconomic status (professional downgrading and loss of work-derived income). There appears to be a great need for legislation that facilitates the relocation of these patients.

Patients' interest in educational programmes on asthma.

The compliance of patients in educational programmes on asthma is sometimes lacking and this may be due in part to patients' scarce interest or refusal to expand their knowledge of the disease. In the present study, we aimed to evaluate the interest of a group of asthmatic patients in education on asthma and to point out the asthma-related topics considered particularly worth discussing. The study was conducted before starting the educational programme. Sixty adult patients with mild-to-moderate asthma were asked to complete a questionnaire, including a group of 14 questions aimed at evaluating the level of patients' interest in various asthma-related topics, one question regarding patients' willingness to attend a small-group educational course on asthma, and a further question asking patients to suggest topics of particular interest for discussion. For each of the first 14 questions, patients indicated their level of interest according to a score ranging 1-3. The sum of the scores obtained for each topic (partial score) and the sum of partial scores (total score) were calculated and classified into three classes of interest (I: low, II: medium; III: high), and the distribution of patients into the three classes was analysed (chi-squared test).(ABSTRACT TRUNCATED AT 250 WORDS)

Occupational asthma: fate and management after the diagnosis.

The clinical and socio-professional fate of subjects with occupational asthma is not univocal. We re-examined twenty-nine subjects diagnosed in our center as suffering from this disease an average 14 months, SE 1.54 after the diagnosis. At the follow-up examination each patient underwent interview, spirometry and methacholine challenge, 18 patients (group A) had ceased exposure to the sensitizing agent but among them only 7 had been relocated in another area of the plant, the others had resigned or retired. The other patients had not changed workplace, 7 (group B) having had intermittent exposure to the offending agent and 4 (group C) having continued to be exposed daily. At the follow-up examination only 9 patients were asymptomatic, each of them belonging to group A, whereas in the other 9 of the same group symptoms persisted, although reduced. In group B and C all patients were still symptomatic and required pharmacologic treatment. Within group A patients who became asymptomatic had shorter duration of symptoms before diagnosis (12.9 months, SE 6.4 vs 23.9, SE 9.7), higher FEV-1 (96.1, SE 6.7 vs 86.9, SE 5.6) and PD20FEV-1 (1773.4 micrograms, SE 590 vs 730.8, SE 295) at the time of the diagnosis and showed a significant (p < 0.01) increase in FEV-1 (from 96.1, SE 6.2 to 101.6, SE 5.5) and a tendency to decrease in bronchial reactivity to methacholine at the follow-up examination. At the time of the follow-up examination only 5 out of 29 patients (17.2%) had been contacted by the compensation board.(ABSTRACT TRUNCATED AT 250 WORDS)