Differences in asthma genetics between Chinese and other populations

Asthma is caused by complex gene-gene and gene-environment interactions. Most asthma genes are not replicable across populations, which is possibly because of differences in the epidemiology of these genes. Our case-control association and next-generation sequencing studies revealed substantial discrepancies in the frequencies of single nucleotide polymorphisms (SNPs) and haplotype blocks for asthma genes between Chinese and other populations. The minor allele frequencies for nearly half of our studied SNPs differed by 0.2 or greater between southern Chinese subjects in Hong Kong and European white populations, African populations, or both. Because genome-wide association studies for asthma have not been performed in Chinese subjects, we cannot tell whether the genomic findings of recent consortium-based genome-wide association studies are applicable to our population. In addition, our group performed Roche 454 pyrosequencing on a 100-kb area spanning each of 10 asthma loci in 24 healthy Hong Kong children. For the 17q21 locus, there was substantial variation in the haplotype structures that were constructed from 224 common SNPs among Hong Kong subjects and 6 ethnic groups under the 1000 Genomes Project. Sixteen mostly small haplotype blocks were formed in Hong Kong, whereas 6 haplotype blocks were identified in Han Chinese in Beijing and central European subjects and 11 and 19 blocks were identified in Puerto Rican and Yoruba African subjects. In conclusion, differences in allele frequencies of asthma genes and haplotype structures of asthma loci are found between Chinese subjects and other ethnic groups. These sequence variations must be considered during the selection of tagging SNPs for replicating genetic associations between populations.

Recent advances in asthma biomarker research

Asthma is characterized by recurrent and reversible airflow obstruction, which is routinely monitored by history and physical examination, spirometry and home peak flow diaries. As airway inflammation is central to asthma pathogenesis, its monitoring should be part of patient management plans. Fractional exhaled nitric oxide level (FeNO) is the most extensively studied biomarker of airway inflammation, and FeNO references were higher in Chinese (Asians) than Whites. Published evidence was inconclusive as to whether FeNO is a useful management strategy for asthma. Other biomarkers include direct (histamine, methacholine) and indirect (adenosine, hypertonic saline) challenges of bronchial hyperresponsiveness (BHR), induced sputum and exhaled breath condensate (EBC). A management strategy that normalized sputum eosinophils among adult patients resulted in reductions of BHR and asthma exacerbations. However, subsequent adult and pediatric studies failed to replicate these benefits. Asthma phenotypes as defined by inflammatory cell populations in sputum were also not stable over a 12-month period. A recent meta-analysis concluded that induced sputum is not accurate enough to be applied in routine monitoring of childhood asthma. There is poor correlation between biomarkers that reflect different asthma dimensions: spirometry (airway caliber), BHR (airway reactivity) and FeNO or induced sputum (airway inflammation). Lastly, EBC is easily obtained noninvasively by cooling expired air. Many biomarkers ranging from acidity (pH), leukotrienes, aldehydes, cytokines to growth factors have been described. However, significant overlap between groups and technical difficulty in measuring low levels of inflammatory molecules are the major obstacles for EBC research. Metabolomics is an emerging analytical method for EBC biomarkers. In conclusion, both FeNO and induced sputum are useful asthma biomarkers. However, they will only form part of the clinical picture. Longitudinal studies with focused hypotheses and well-designed protocols are needed to establish the roles of these biomarkers in asthma management. The measurement of biomarkers in EBC remains a research tool.

Changing prevalence of allergic diseases in the Asia-pacific region

Asia-Pacific is one of the most densely populated regions of the world and is experiencing rapid economic changes and urbanization. Environmental pollution is a significant problem associated with the rapid modernization of many cities in South Asia. It is not surprising that the prevalences of asthma and allergies are increasing rapidly, although the underlying reasons remain largely unknown. Many studies from this region have documented the changing prevalence of allergic diseases in various parts of the world. However, the methodologies used were neither standardized nor validated, making the results difficult to evaluate. The International Study of Asthma and Allergies in Childhood (ISAAC) has provided a global epidemiology map of asthma and allergic diseases, as well as the trend of changes in the prevalence of these diseases. Allergic sensitization is extremely common in many Asian communities. However, the prevalence of allergic diseases remains relatively rare. The rapid urbanization in the region, which increases environmental pollution and can affect the rural environment, will likely increase the prevalence of asthma and allergies in Asia.

Air pollution and chronic obstructive pulmonary disease

Limited data suggest that outdoor air pollution (such as ambient air pollution or traffic-related air pollution) and indoor air pollution (such as second-hand smoking and biomass fuel combustion exposure) are associated with the development of chronic obstructive pulmonary disease (COPD), but there is insufficient evidence to prove a causal relationship at this stage. It also appears that outdoor air pollution is a significant environmental trigger for acute exacerbation of COPD, leading to increasing symptoms, emergency department visits, hospital admissions and even mortality. Improving ambient air pollution and decreasing indoor biomass combustion exposure by improving home ventilation are effective measures that may substantially improve the health of the general public.

An adjunct intervention for management of acute exacerbation of chronic obstructive pulmonary disease (AECOPD)

OBJECTIVES

Application of transcutaneous electrical nerve stimulation over acupuncture points (Acu-TENS) is a noninvasive intervention that has recently been shown to alleviate dyspnea in patients with stable chronic obstructive pulmonary disease (COPD). This case report aims to explore the role of Acu-TENS in patients diagnosed with COPD during the acute exacerbation.

STUDY DESIGN

The study design was a case report.

SETTING

The study was conducted in an inpatient setting.

SUBJECT

The subject was a 74-year-old man admitted to the hospital due to acute exacerbation of COPD (AECOPD).

INTERVENTION

Treatment consisted of application of TENS on EX-B1 (Dingchuan) for 45 minutes.

OUTCOME MEASURES

Oxygen saturation, heart rate, and dyspnea score were measured before, immediately after, and 45 minutes after Acu-TENS intervention. Other than the physiologic measures, 10 mL of venous blood was taken from the cubital vein for assessment of β-endorphin level, white blood cell count, tumor necrosis factor-α (TNF-α), and C-reactive protein (CRP) level before and immediately postintervention.

RESULTS

Postintervention, improved oxygen saturation, and reduction in heart rate and dyspneic sensation were observed accompanied by a raised blood β-endorphin level but the level of white blood cell count, TNF-α, and CRP remain unchanged.

CONCLUSIONS

Application of 45 minutes Acu-TENS appeared to alleviate symptoms in a patient with AECOPD. The role of adjunctive Acu-TENS therapy during acute exacerbation warrants further investigation.

Evaluation of the asthma control test: a reliable determinant of disease stability and a predictor of future exacerbations

BACKGROUND AND OBJECTIVE

This study assessed the asthma control test (ACT) cut-off values for asthma control according to the Global Initiative for Asthma guideline in adults and the effectiveness of ACT scores in predicting exacerbations and serial changes in ACT scores over time in relation to treatment decisions.

METHODS

Subjects completed ACT together with same-day spirometry and fractional concentration of exhaled nitric oxide (FeNO) measurement at baseline and at 3 months. Physicians, blinded to the ACT scores and FeNO values, assessed the patient's asthma control in the past month and adjusted the asthma medications according to management guidelines. Asthma exacerbations and urgent health-care utilization (HCU) at 6 months were recorded.

RESULTS

Three hundred seventy-nine (120 men) asthmatics completed the study. The ACT cut-off for uncontrolled and partly controlled asthma were ≤19 (sensitivity 0.74, specificity 0.67, % correctly classified 69.5) and ≤22, respectively (sensitivity 0.73, specificity 0.71, % correctly classified 72.1). Baseline ACT score had an odds ratio of 2.34 (95% confidence interval: 1.48-3.69) and 2.66 (1.70-4.18) for urgent HCU and exacerbations, respectively, at 6 months (P < 0.0001). However, baseline FeNO and spirometry values had no association with urgent HCU and exacerbations. The 3-month ACT score of ≤20 correlated best with step-up of asthma medications (sensitivity 0.65, specificity 0.81, % correctly classified 72.8). For serial changes of ACT scores over 3 months, the cut-off value was best at ≤3 for treatment decisions with low sensitivity (0.23) and % correctly classified (57.3%) values.

CONCLUSIONS

Single measurement of ACT is useful for assessing asthma control, prediction of exacerbation and changes in treatment decisions.

Relationship between asthma control status, the Asthma Control Test™ and urgent health-care utilization in Asia

BACKGROUND AND OBJECTIVE

Accurate assessment of control is an integral part of asthma management. We investigated the relationship between control status derived from the Global Initiative for Asthma (GINA), the Asthma Control Test (ACT) and urgent health-care utilization.

METHODS

Asthma Insights and Reality in Asia-Pacific Phase 2 (AIRIAP 2) was a cross-sectional, community-based survey of 4805 subjects with asthma from urban centres across Asia. A symptom control index was derived from the AIRIAP 2 questionnaire using the GINA control criteria for day- and night-time symptoms, need for rescue medication, activity limitation and exacerbations; lung function was excluded. The main outcomes were asthma control, based on these GINA criteria and the ACT, and the relationship between control and self-reported urgent health-care utilization (hospitalization, emergency room visits or other unscheduled urgent visits) related to asthma over the previous 12months.

RESULTS

Each of the symptom criteria was significantly associated with urgent health-care utilization, with odds ratios (ORs) ranging from 2.25 (95% confidence interval (CI): 1.94-2.61) for daytime symptoms to 2.57 (95% CI: 2.29-2.90) for nocturnal awakening. Similarly, control status was significantly associated with urgent health-care utilization, with ORs of 0.19 (95% CI: 0.13-0.28), 0.70 (95% CI: 0.65-0.76) and 1.00 for controlled, partly controlled and uncontrolled, respectively. The optimal ACT cut-off score for identifying uncontrolled asthma was ≤19 for subjects aged ≥12years. Urgent health-care utilization was reported by 57.2% versus 28.7% of patients scoring ≤19 versus >19 (P<0.001).

CONCLUSIONS

The GINA control classification and the ACT are valid symptom-based measures that are significantly associated with urgent health-care utilization.

Prevalence of allergic rhinitis and its associated morbidity in adults with asthma: a multicentre study

OBJECTIVES

To assess the prevalence of allergic rhinitis in adult patients with asthma in Hong Kong, and to compare the morbidity endured by asthma patients with and without allergic rhinitis.

DESIGN

Cross-sectional study.

SETTING

Respiratory clinics of four major public hospitals in Hong Kong.

PATIENTS

A total of 600 adults with asthma were recruited from March to May 2007.

MAIN OUTCOME MEASURES

Doctors and patients completed separate questionnaires evaluating symptoms, treatment, and health care utilisation. Spirometry data were obtained for a subgroup of patients at the time of survey completion.

RESULTS

The patients consisted of 267 males and 333 females, with 251 having spirometry data. The mean pre-bronchodilator 1-second forced expiratory volume predicted among those who had spirometry performed was 88% (standard deviation, 28%). In all, 50% of the patients had intermittent and 50% had persistent asthma. Over three quarters (463/600; 77%) of patients had experienced allergic rhinitis symptoms in the past 12 months, of whom 96% had a previous diagnosis of allergic rhinitis. Asthmatics without allergic rhinitis symptoms had higher rates of visits to doctors, pharmacy visits, emergency department attendances, and hospitalisations for asthma than those with both conditions. Among subjects with asthma and allergic rhinitis, those taking nasal steroid (226/463; 49%) had lower rates of emergency department visits (13 vs 25%, P=0.002) and hospitalisations (7 vs 13%, P=0.045) for asthma than those who were not.

CONCLUSION

Allergic rhinitis is a common co-morbid condition of asthma in this hospital clinic cohort. Treatment of allergic rhinitis with intra-nasal steroid was associated with less health care utilisation for asthma.

Validation of Embletta portable diagnostic system for identifying patients with suspected obstructive sleep apnoea syndrome (OSAS)

The Embletta portable diagnostic system is highly sensitive and specific in quantifying the AHI and differentiating obstructive and supine events when compared against hospital-based PSG in patients with suspected OSAS. The simple device may be useful for screening and diagnostic purpose when access to PSG is limited.

BACKGROUND AND OBJECTIVES

This study aimed to evaluate the diagnostic accuracy of Embletta portable diagnostic system (PDS, Medcare, Reykjavik, Iceland) for the screening of sleep apnoea in clinical practice.

METHODS

The Embletta PDS is a digital three-channel recording device that measures airflow through a nasal cannula connected to a pressure transducer, oxygen saturation plus both respiratory and abdominal movements via built-in effort and body position sensors. An AHI is determined based on recording time. Nocturnal polysomnography (Alice 4, Healthdyne, Atlanta, USA), with airflow measured by a nasal pressure transducer (PTAF2, Pro-Tech, Woodinville, WA, USA)) and Embletta PDS recordings, was performed simultaneously in consecutive patients with suspected OSA syndrome. The PSG recordings were analysed manually by a blinded investigator.

RESULTS

Ninety subjects were recruited and 10 failed Embletta PDS studies due to measurement failure. Among the remaining 80 subjects, 63 were males. The mean age (SD) was 51.4 (11.9) years old, BMI 27.1(4.2) kg/m2, neck circumference 38.6 (3.6) cm and Epworth Sleepiness Score 9.7 (5.3). The AHI obtained by the Embletta PDS correlated closely with that obtained by PSG (Pearson correlation, r=0.979, P<0.001). Comparison of AHI based on the Embletta PDS against the PSG demonstrated high sensitivity at AHI>or=5/h (sensitivity 0.924 and specificity 0.857) and high specificity at AHI>or=20/h (sensitivity 0.853 and specificity 0.957).

CONCLUSIONS

The Embletta PDS is a highly sensitive and specific screening device in quantifying AHI when compared against PSG in patients with suspected OSA syndrome.

Effect of 4 weeks of Acu-TENS on functional capacity and beta-endorphin level in subjects with chronic obstructive pulmonary disease: a randomized controlled trial

Our recent studies showed that one session of transcutaneous electrical nerve stimulation on acupoints (Acu-TENS) improved forced expiratory volume in 1s (FEV(1)) in patients with chronic obstructive pulmonary disease (COPD). This study investigated the effect of 4-week Acu-TENS on physical and psychosocial function in these patients. Twenty-eight patients were randomly allocated to receive 4-weeks of 45-min, 5-days/week, of either Acu-TENS (over Dingchuan), Placebo-TENS (same protocol without electrical output), or Sham-TENS (over the patellae). Variables measured before and after intervention included FEV(1), forced vital capacity (FVC), 6-min walk distance (6MWD), St. George's Respiratory Questionnaire score (SGRQ), beta-endorphin and blood inflammatory marker levels. Only the Acu-TENS group attained significant improvement in FEV(1) (p=0.046), physical activity (p=0.007) and total SGRQ score (p=0.028). The increase in beta-endorphin (p=0.012) correlated positively with the improvement in FEV(1) (r=0.526, p=0.008). To conclude, 4 weeks of Acu-TENS improved the functional capacity of patients with COPD, probably due to the bronchodilation induced by beta-endorphin elevation.

Are Hong Kong doctors following the Global Initiative for Asthma guidelines: a questionnaire "Survey on Asthma Management"?

OBJECTIVE

To assess the standard of asthma management by doctors in Hong Kong.

DESIGN

Cross-sectional postal questionnaire survey.

SETTING

Hong Kong.

PARTICIPANTS

Practising doctors registered with the Medical Council of Hong Kong were sent a questionnaire between August and December 2007.

MAIN OUTCOME MEASURES

Respondents' responses to questions on demographic data, parameters routinely used to assess asthma control, the pattern of asthma medication prescribing, and seven different case scenarios assessing their ability to classify asthma control and management. RESULTS. We received 410 completed questionnaires from general practitioners (55%), internists (22%), paediatricians (11%), and other specialists (12%). The majority (82%) explained the pathology of asthma to at least some of their patients and tried to identify aggravating factors of the asthma (91%). Fewer observed the inhalation technique of their patients (68%) and prescribed a written asthma management plan (33%). The main medications prescribed to adults and children with asthma were inhaled corticosteroids, inhaled short-acting beta-2 agonists, and combinations of an inhaled corticosteroid and a long-acting beta-2 agonist. In adults and children, long-acting beta-2 agonist alone (without inhaled corticosteroid) was being used to treat asthma by 45% and 36% of the doctors, respectively. Also, 94% of the respondents correctly classified the control status in four out of the seven case scenarios and 31% chose the correct medications when responding to seven of the 14 questions asked.

CONCLUSIONS

Asthma management practice of Hong Kong doctors falls short of the standards recommended by international guidelines. More effort in improving their knowledge is urgently warranted.

Endoscopic ultrasonography-guided fine-needle aspiration in the management of mediastinal diseases: local experience of a novel investigation

OBJECTIVE

To study the efficacy and safety of endoscopic ultrasonography-guided fine-needle aspiration in the management of mediastinal diseases in Hong Kong.

DESIGN

Retrospective review of prospectively collected data.

SETTING

University teaching hospital, Hong Kong.

PATIENTS

A total of 125 consecutive patients with various mediastinal and pulmonary lesions that underwent trans-oesophageal endoscopic ultrasonography-guided fine-needle aspiration from July 1998 to June 2007.

MAIN OUTCOME MEASURES

The diagnostic accuracy and safety of the procedure and its influence in patient management.

RESULTS

Malignancy was confirmed in 62 (50%) of the patients and excluded in 42 (34%). The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of endoscopic ultrasonography-guided fine-needle aspiration in diagnosing mediastinal malignancies were 75% (95% confidence interval, 64-83%), 100% (90-100%), 100% (93-100%), 67% (54-78%), and 83%, respectively. Eighty-six (69%) of the patients had their initial plan of invasive investigations changed. Only one (0.8%) patient developed a septic complication in a mediastinal cyst after puncturing, and was treated surgically.

CONCLUSIONS

Trans-oesophageal endoscopic ultrasonography-guided fine-needle aspiration is a minimally invasive, effective, and safe method of diagnosing malignant mediastinal disease. It may reduce the need for other invasive investigations.

CXCL 9 and CXCL 10 as Sensitive markers of disease activity in patients with rheumatoid arthritis

OBJECTIVE

To assess whether serum levels of CC and CXC chemokines correlate with disease activity in patients with rheumatoid arthritis (RA), and to determine whether these effects predict clinical response.

METHODS

Serum levels of the chemokines CC (CCL2, CCL5) and CXC (CXCL8, CXCL9, CXCL10) were quantified at baseline and after 12 weeks of treatment with disease-modifying antirheumatic drugs or biologic agents in 28 patients using flow cytometry. Serum from 40 healthy individuals was collected for comparison at baseline. Response to treatment was classified according to the European League Against Rheumatism (EULAR) response criteria. Remission of disease was defined as a Disease Activity Score < 2.6.

RESULTS

The baseline serum concentrations of CC and CXC chemokines were significantly elevated in patients with active RA compared to healthy controls (p < 0.05) except for CCL2. Significant improvement in all disease activity measurements was observed after 12 weeks of treatment. Seventeen (60.7%) patients achieved good to moderate response based on the EULAR response criteria, and 5 (17.9%) patients achieved remission. The improvement in clinical activity in patients with RA was accompanied by a significant reduction in the serum concentration of CXCL9 and CXCL10 (p < 0.001). A significant reduction in the serum level of CXCL10 was also observed in the group that achieved EULAR response. Serum concentration of CCL5 remained significantly elevated in patients with RA (n = 5) who achieved remission compared to the healthy controls (p < 0.05).

CONCLUSION

Serum concentration of CXCL9 and CXCL10 may serve as sensitive biomarkers for disease activity in patients with RA.

Management of patients admitted with pneumothorax: a multi-centre study of the practice and outcomes in Hong Kong

OBJECTIVE

To examine the management practice of pneumothorax in hospitalised patients in Hong Kong, especially the choice of drainage options and their success rates, as well as the factors associated with procedural failures.

DESIGN

Retrospective study.

SETTING

Multi-centre study involving 12 public hospitals in Hong Kong.

PATIENTS

All adult patients admitted as an emergency in the year 2004 with a discharge diagnosis of 'pneumothorax' were included. Data on the management and outcomes of the various types of pneumothoraces were collected from their case records.

RESULTS

Altogether these patients had 1091 episodes (476 primary spontaneous pneumothoraces, 483 secondary spontaneous pneumothoraces, 87 iatrogenic pneumothoraces, and 45 traumatic pneumothoraces). Conservative treatment was offered in 182 (17%) episodes, which were more common among patients with small primary spontaneous pneumothoraces (71%). Simple aspiration was performed to treat 122 (11%) of such episodes, and had a success rate of 15%. Aspiration failure was associated with having a pneumothorax of size 2 cm or larger (odds ratio=3.7; 95% confidence interval, 1.2-11.5; P=0.03) and a smoking history (4.1; 1.2-14.3; P=0.03). Intercostal tube drainage was employed in 890 (82%) episodes, with a success rate of 77%. Failure of intercostal tube drainage was associated with application of suction (odds ratio=4.1; 95% confidence interval, 2.8-5.9; P<0.001) and presence of any tube complications (1.55; 1.0-2.3; P=0.03). Small-bore catheters (<14 French) were used in 12 (1%) of the episodes only. Tube complications were encountered in 214 (24%) episodes.

CONCLUSION

Notwithstanding recommendations from international guidelines, simple aspiration and intercostal tube drainage with small-bore catheters were not commonly employed in the management of hospitalised patients with the various types of pneumothoraces in Hong Kong.

Can continuous pump feeding reduce the incidence of pneumonia in nasogastric tube-fed patients? A randomized controlled trial

BACKGROUND & AIMS

Continuous pump feeding is often used to reduce aspiration risk in older patients on tube feeding, but its effectiveness in preventing aspiration pneumonia is unproven. A randomized controlled trial was therefore performed to examine the effectiveness of continuous pump feeding in decreasing the incidence of pneumonia in tube-fed older hospital patients.

METHODS

One hundred and seventy eight elderly patients from three convalescence hospitals and one infirmary, on nasogastric tube feeding, were randomly assigned to have intermittent bolus (bolus) or continuous pump (pump) feeding for 4weeks. The primary outcome was the incidence of pneumonia. The secondary outcome was mortality.

RESULTS

Eighty five subjects were randomized into the pump group and 93 in the bolus group. The groups were comparable in age, nutritional and functional status, co-morbidities and history of pneumonia, except that there were more women in the pump group. Within 4weeks, 15 subjects (17.6%) in the pump group and 18 (19.4%) in the bolus group developed pneumonia. Seven subjects (8.2%) in pump group and 13 subjects (14.0%) in bolus group died. There was no significant difference in either pneumonia or death rates between the two groups.

CONCLUSION

Continuous pump feeding did not significantly affect the rates of pneumonia or mortality in tube-fed older hospital patients when compared with intermittent bolus feeding.

Effect of Acu-TENS on post-exercise expiratory lung volume in subjects with asthma-A randomized controlled trial

This study examined the effect of transcutaneous electrical nerve stimulation applied over acupoints (Acu-TENS) on forced expiratory volume, in patients with asthma, after exercise. Thirty subjects were randomly assigned to three groups. Group 1 received Acu-TENS over acupuncture points Lieque and Dingchuan for 45 min prior to a symptom-limited treadmill exercise test. Group 2 had Acu-TENS similarly applied prior to and throughout the exercise test. Group 3 mimicked Group 1 but without any electrical output from the device. Forced expiratory volume in one second (FEV(1)) and forced vital capacity (FVC) were recorded before, immediately after and at 20-min intervals post-exercise for 1h. Immediately after exercise, FEV(1) and FVC rose in Group 2 (p=0.015), but decreased in Group 1 and more so in Group 3. The differences became even more marked at 20, 40 and 60 min. Adjunctive Acu-TENS therapy appears to reduce decline of FEV(1) following exercise training in patients with asthma.

Predicting changes in clinical status of young asthmatics: clinical scores or objective parameters?

Preventing asthma exacerbation is an important goal of asthma management. The existing clinical tools are not good in predicting asthma exacerbations in young children. Childhood Asthma Control Test (C-ACT) was recently published to be a simple tool for assessing disease control in young children. This study investigated C-ACT and other disease-related factors for indicating longitudinal changes in asthma status and predicting asthma exacerbations. During the same clinic visit, asthma patients aged 4-11 years completed the Chinese version of C-ACT and underwent exhaled nitric oxide and spirometric measurements. Blinded to these results, the same investigator assigned Disease Severity Score (DSS) and rated asthma control according to Global Initiative for Asthma. Asthma exacerbations during the next 6 months were recorded. Ninety-seven patients were recruited, with their mean (standard deviation [SD]) age being 9.2 (2.0) years. Thirty-six (37.1%) patients had uncontrolled asthma at baseline. C-ACT, DSS, and FEV(1) differed among patients with different control status (P < 0.001 for C-ACT and DSS; P = 0.028 for FEV(1)). Thirty-two patients had asthma exacerbations during the 6-month follow-up. Changes in patients' C-ACT scores correlated with changes in asthma control status, DSS, and FEV(1) (P = 0.019, 0.034, and 0.020, respectively). C-ACT score was lower among patients with asthma exacerbations (mean [SD]: 22.9 [4.2] vs. 24.5 [2.1]; P = 0.015). Logistic regression confirmed that the occurrence of asthma exacerbations was associated only with baseline C-ACT (B = -0.203, P = 0.042). In conclusion, C-ACT is better than DSS and objective parameters in reflecting changes in asthma status and predicting asthma exacerbations in young children.

Identifying uncontrolled asthma in young children: clinical scores or objective variables?

OBJECTIVE

Several international asthma guidelines emphasize the importance of assessing asthma control. However, there is limited data on the usefulness of available assessment tools in indicating disease control in young asthmatics. This study investigated the ability of Chinese version of Childhood Asthma Control Test (C-ACT) and other disease-related factors in identifying uncontrolled asthma (UA) in young children.

METHODS

During the same clinic visit, asthma patients 4 to 11 years of age completed C-ACT and underwent exhaled nitric oxide and spirometric measurements. Blinded to these results, the same investigator assigned Disease Severity Score (DSS) and rated asthma control according to Global Initiative for Asthma.

RESULTS

The mean (SD) age of 113 recruited patients was 9.1 (2.0) years, and 35% of them had UA. C-ACT, DSS and forced expiratory volume in 1 second (FEV(1)) differed among patients with different control status (p < 0.001 for C-ACT and DSS; p = 0.014 for FEV(1)). Logistic regression confirmed that UA was associated with DSS (p < 0.001), PEF (p = 0.002), C-ACT (p = 0.011), and FEV(1) (p = 0.012). By ROC analysis, C-ACT and DSS were the best predictors for UA (p < 0.001), followed by PEF (p = 0.006) and FEV(1) (p = 0.007). When analyzed by the Classification and Regression Tree (CART) approach, the sequential use of DSS and C-ACT had 77% sensitivity and 84% specificity in identifying UA.

CONCLUSIONS

C-ACT is better than objective parameters in identifying young Chinese children with UA.

Geographic differences in clinical characteristics and management of COPD: the EPOCA study

AIMS

Data on differences in clinical characteristics and management of COPD in different countries and settings are limited. We aimed to characterize the profile of patients with COPD in a number of countries and their treatment in order to evaluate adherence to recommendations of international guidelines.

METHOD

This was an observational, international, cross-sectional study on patients with physician-diagnosed COPD. Demographic and clinical characteristics, risk factors, and treatment were collected by their physician via an internet web-based questionnaire developed for the study.

RESULTS

A total of 77 investigators from 17 countries provided data on 833 patients. The countries with the highest number of patients included were: Argentina (128), Ecuador (134), Spain (162), and Hong Kong (153). Overall, 79.3% were men and 81% former smokers, with a mean FEV1 = 42.7%, ranging from 34.3% in Hong Kong to 58.8% in Ecuador. Patients reported a mean of 1.6 exacerbations the previous year, with this frequency being significantly and negatively correlated with FEV1 (%) (r = -0.256; p < 0.0001). Treatment with short-acting bronchodilators and theophyllines was more frequent in Ecuador and Hong Kong compared with Spain and Argentina, and in patients belonging to lower socioeconomic levels (p < 0.0001 for all comparisons). Inadequacy of treatment with inhaled corticosteroids and theophyllines was high, with significant differences among countries.

CONCLUSIONS

Differences in the clinical characteristics and management of COPD were significant across countries. Adherence to international guidelines appears to be low. Efforts should be made to disseminate and adapt guidelines to the socioeconomic reality of different settings.

Asthma Control Test correlates well with the treatment decisions made by asthma specialists

BACKGROUND AND OBJECTIVE

Poor assessment of asthma control results in suboptimal treatment. Identifying parameters that accurately assess control will benefit treatment decisions. The Asthma Control Test (ACT) is a five-item questionnaire for the assessment of asthma control. This study evaluated its correlation with the treatment decisions made by asthma specialists in an outpatient clinic setting, and compared its performance with other conventional parameters including spirometry, PEF rate (PEFR), fractional exhaled nitric oxide (FeNO) and BHR.

METHODS

The 383 (122 men) study subjects completed a 1-month diary on symptoms and PEFR before the assessment. All subjects then completed the ACT together with same-day spirometry and FeNO measurement. BHR to methacholine was performed in 73 subjects in the week before assessment. Asthma specialists, blinded to the results of the ACT, FeNO and BHR (but not spirometry and PEFR), assessed the patients' level of control according to the 2006 version of the Global Initiative for Asthma guidelines and made appropriate treatment decision.

RESULTS

The group mean (SD) age was 46.1 (13.4) years with pre-bronchodilator FEV(1) 84.72 (20.81) % predicted. Receiver operating characteristic (ROC) curve analysis found that an ACT score of < or = 20 best correlated with uncontrolled asthma (area under curve (AUC) = 0.76) with a sensitivity of 70.5%, specificity 76.0%, positive predictive value 76.2% and negative predictive value 70.2% for predicting step-up of asthma therapy. On ROC analysis, the ACT score had the highest AUC (0.81 (P < 0.001)) for changing asthma therapy when compared with FeNO, spirometry, PEFR and BHR parameters

CONCLUSIONS

The ACT correlated better with treatment decisions made by asthma specialists than spirometry, PEFR and FeNO.

Activation of peripheral Th17 lymphocytes in patients with asthma

A recently identified interleukin (IL)-17-producing T-helper (Th) lymphocyte subset, which comprises Th17 cells producing hallmark cytokines IL-17A, IL-17F and IL-22, is involved in chronic inflammatory diseases. Elevated gene and protein expressions of IL-17 are manifested in allergic asthma. We further characterized the activation of Th17 cells in asthmatic patients. Peripheral blood mononuclear cells (PBMC) were purified from 31 asthmatic patients and 20 sex- and age-matched control subjects. The number of IL-17A secreting cells in peripheral blood was enumerated by enzyme-linked immunosorbent spot assay. Cell surface expression of Th17-related chemokine receptor CCR6, and plasma level of IL-17A, IL-17F and IL-22, and ex vivo production of IL-17A and IL-22 were measured by flow cytometry and enzyme-linked immunosorbent assay, respectively. The number of peripheral Th17 lymphocytes, expression of CCR6 on Th cells, and ex vivo IL-23, anti-CD3 and anti-CD28 induced production of IL-22 by PBMC were significantly elevated in asthmatic patients compared with control subjects (all p < 0.01). This clinical study further confirmed increased number of peripheral Th17 lymphocytes and cell surface expression of CCR6 receptors on Th cells in asthmatic patients. Pro-inflammatory cytokine IL-23 can exacerbate disease severity by activating pathogenic Th17 lymphocytes to release downstream inflammatory cytokine IL-22 in asthma.

Expression and functional analysis of toll-like receptors of peripheral blood cells in asthmatic patients: implication for immunopathological mechanism in asthma

BACKGROUND

We investigated the expression profile of toll-like receptors (TLRs) and TLR ligand-activated production profile of asthma-related inflammatory cytokines in asthmatic patients. The expression of TLR1-8 on monocytes, CD4+ T helper lymphocytes, CD8+ T cytotoxic lymphocytes, CD19+ B lymphocytes, and dendritic cells, and ex vivo production of cytokines from peripheral blood mononuclear cells activated by TLR ligands were measured by flow cytometry.

DISCUSSION

Ex vivo productions of TNF-alpha, IL-10, and IL-1beta by TLR4 and TLR5 ligand LPS and flagellin were significantly lower in asthmatic patients (all P < 0.05). Expression of TLR4 and TLR5 was also found to be significantly lower in asthmatic patients when compared to that of control subjects (all P < 0.05). Therefore, the decreased activation of TLR4 and TLR5 in asthmatic patients might contribute to the immunopathological mechanisms of asthma by reducing the release of Th1 and anti-inflammatory cytokines.

Prevalence and risk factors of airflow obstruction in an elderly Chinese population

It is common practice to use a forced expiratory volume in one second (FEV(1))/ forced vital capacity (FVC) ratio of <70% as evidence of airflow obstruction. As the FEV(1)/FVC ratio falls with age, the lower limit of normal range (LLN), defined as the bottom 5% in a health reference population, of FEV(1)/FVC ratio has been suggested as a better index to reduce over-diagnosis of chronic obstructive pulmonary disease (COPD), particularly in the elderly. However, there are no large scale studies that focus on the diagnosis of COPD in the elderly based on these definitions. The present prospective epidemiological study involved 1,149 elderly subjects aged > or =60 yrs in the community. Detailed questionnaires, pre- and post-bronchodilator spirometry were performed. In total, 1,008 subjects (mean age 74.2+/-6.4 yrs; 271 males) completed satisfactory spirometry testing. Airflow obstruction was present in 25.9% as defined by the post-bronchodilator FEV(1)/FVC ratio of <70% and in 12.4% defined by the LLN of FEV(1)/FVC ratio. Moderate COPD, at least, was found in 14.0% of patients according to the post-bronchodilator FEV(1)/FVC ratio of <70% and in 8.5% of patients according to LLN of FEV(1)/FVC ratio. In the present elderly Chinese population (mostly females, with low education level and previous exposure to biomass during formative years), the prevalence of chronic obstructive pulmonary disease varied markedly depending on definitions adopted. Further longitudinal studies are needed to determine the precise definition of chronic obstructive pulmonary disease.