[Early detection of smoking related chronic obstructive pulmonary disease in Vietnam]

Diagnostic accuracy of screening tools for chronic obstructive pulmonary disease in primary health care: Rapid evidence synthesis

Background:

Chronic obstructive pulmonary disease (COPD) contributed significantly to burden of diseases in India, with missed, incorrect, and delayed diagnosis in primary care. We conducted a rapid evidence synthesis, to summarize the evidence on accuracy of the screening tests for COPD in primary health care on request form State Health Resource Centre, Chhattisgarh.

Methods:

Considering the rapid nature of decision making, our approach was to first search for existing systematic reviews. We identified one existing systematic review on the topic with the search conducted until 2014. We updated the review by searching in two major databases screened, title/abstracts, and full texts of studies as per eligibility criteria and extracted relevant data. A narrative synthesis was conducted.

Results:

We retrieved 7,007 and included five new studies, to add to 10 studies of the existing systematic review. Overall, 13 studies assessed diagnostic accuracy of screening questionnaires [e.g., COPD Diagnostic Questionnaire (CDQ)], five assessed handheld flow meters (COPD6 and PICO-6), and four assessed the combination of both the tests. The CDQ questionnaire using a score threshold ≥16.5 or >17 demonstrated comparatively a higher sensitivity both in pooled result for ever-smokers [87.5% (95% CI 83.1--90.9%)] and among the adults >35 years [73.8--93% (95% CI 69--98%)] when compared to a different score threshold of CDQ and other questionnaires. Handheld flow meters reported a pooled high sensitivity of 79.9% (95% CI 74.2--84.7%) in ever-smokers and 87.9% in adults with age >35 years.

Conclusions:

The need for better diagnosis of COPD in primary healthcare can be addressed by using of COPD Diagnostic Questionnaire alone or in combination with hand-held flow meters. There is scope for more implementation research on the domain.

Study of the role of exhaled nitric oxide (NO) in predicting controlled or uncontrolled asthma in asthmatic children

Background

Exhaled nitric oxide (NO), especially fractional concentration of exhaled NO (FE_NO) has been used to predict the responsiveness to inhaled corticosteroid (ICS) in children with asthma. However, the use of exhaled NO for predicting asthma control in children is still controversial.

Methods

This was a perspective observational study. Asthmatic children who were naïve to inhaled corticosteroid (ICS) were included in the present study. The measurements of FE_NO and CA_NO (concentration of NO in the gas phase of the alveolar), spirometry, blood eosinophil counts (BEC), and total IgE levels were done for each asthmatic child. All study subjects started proper asthma treatment after the enrollment.

Results

Ninety three asthmatic children (9±3 years) with moderate (63.4%) to severe (36.6%) asthma were included and finished the 3-month study. The levels of FE_NO and CA_NO at inclusion were 37±11 ppb and 5.8±1.4 ppb, respectively; the mean of BEC was 617±258 cells/μL; the level of total IgE was 1563±576 UI/mL; 89% of subjects were positive for at least one respiratory allergen. The percentage of severe asthma was reduced significantly after 3 months (P<0.001). Well controlled asthma subjects at 3 months had higher levels of FE_NO and lower levels of CA_NO at inclusion (P<0.05 and P<0.05). FE_NO<20 ppb or CA_NO>5ppb had a risk of uncontrolled asthma at 3 months (OR: 1.7, CI 95% [(0.8) - (3.3)], P<0.05; OR: 1.9, CI 95% [(0.9) - (2.7)], P<0.05; respectively). FE_NO>35 ppb at inclusion had a positive predictive value for asthma control at 3 months (OR: 3.5, CI 95% [2.2-5.9], P<0.01).

Conclusions

Exhaled NO is a biomarker of asthma which may have a potential role to predict the control of asthma in short-term follow up in asthmatic children.

Accuracy of Vitalograph lung monitor as a screening test for COPD in primary care

Microspirometry may be useful as the second stage of a screening pathway among patients reporting respiratory symptoms. We assessed sensitivity and specificity of the Vitalograph® lung monitor compared with post-bronchodilator confirmatory spirometry (ndd Easy on-PC) among primary care chronic obstructive pulmonary disease (COPD) patients within the Birmingham COPD cohort. We report a case–control analysis within 71 general practices in the UK. Eligible patients were aged ≥40 years who were either on a clinical COPD register or reported chronic respiratory symptoms on a questionnaire. Participants performed pre- and post-bronchodilator microspirometry, prior to confirmatory spirometry. Out of the 544 participants, COPD was confirmed in 337 according to post-bronchodilator confirmatory spirometry. Pre-bronchodilator, using the LLN as a cut-point, the lung monitor had a sensitivity of 50.5% (95% CI 45.0%, 55.9%) and a specificity of 99.0% (95% CI 96.6%, 99.9%) in our sample. Using a fixed ratio of FEV₁/FEV₆ < 0.7 to define obstruction in the lung monitor, sensitivity increased (58.8%; 95% CI 53.0, 63.8) while specificity was virtually identical (98.6%; 95% CI 95.8, 99.7). Within our sample, the optimal cut-point for the lung monitor was FEV₁/FEV₆ < 0.78, with sensitivity of 82.8% (95% CI 78.3%, 86.7%) and specificity of 85.0% (95% CI 79.4%, 89.6%). Test performance of the lung monitor was unaffected by bronchodilation. The lung monitor could be used in primary care without a bronchodilator using a simple ratio of FEV₁/FEV₆ as part of a screening pathway for COPD among patients reporting respiratory symptoms.

Clinical and Functional Characteristics of Subjects with Asthma, COPD, and Asthma-COPD Overlap: A Multicentre Study in Vietnam

Introduction

Subjects with asthma-chronic obstructive pulmonary disease (COPD) overlap (ACO) share common features of patients with asthma and COPD. Our study was planned to describe the clinical and functional features of subjects with ACO compared to asthma and COPD patients.

Subjects and Methods

Study subjects who met the inclusion criteria were classified into three different groups: asthma, COPD, and ACO groups. All study subjects underwent clinical examination and biological and functional testing. They were then followed for 6 months to evaluate the response to conventional treatment.

Results

From March 2015 to March 2017, 76 asthmatic (mean age: 41 ± 22 years), 74 COPD (59 ± 13 years), and 59 ACO (52 ± 14 years) subjects were included. The percentage of subjects with dyspnea on excretion in the ACO group was higher than that in asthma and COPD groups (P < 0.001 and P < 0.05, resp.). Subjects with COPD and ACO had significant airflow limitation (FEV1) compared to asthma (64 ± 17% and 54 ± 14% versus 80 ± 22%; P < 0.01 and P < 0.01, resp.). The levels of FENO in subjects with asthma and ACO were significantly higher than those in subjects with COPD (46 ± 28 ppb and 34 ± 12 ppb versus 15 ± 8 ppb; P < 0.001 and P < 0.001, resp.). VO2 max and 6MWD were improved in study subjects after 6 months of treatment. Increased CANO and AHI > 15/hour had a significant probability of risk for ACO (OR = 33.2, P < 0.001, and OR = 3.4, P < 0.05, resp.).

Conclusion

Subjects with ACO share the common clinical and functional characteristics of asthma and COPD but are more likely to have sleep apnea. The majority of patients with ACO have a favourable response to combined treatment.

Validation of the portable Air-Smart Spirometer

BACKGROUND

The Air-Smart Spirometer is the first portable device accepted by the European Community (EC) that performs spirometric measurements by a turbine mechanism and displays the results on a smartphone or a tablet.

METHODS

In this multicenter, descriptive and cross-sectional prospective study carried out in 2 hospital centers, we compare FEV1, FVC, FEV1/FVC ratio measured with the Air Smart-Spirometer device and a conventional spirometer, and analyze the ability of this new portable device to detect obstructions. Patients were included for 2 consecutive months. We calculate sensitivity, specificity, positive and negative predictive value (PPV and NPV) and likelihood ratio (LR +, LR-) as well as the Kappa Index to evaluate the concordance between the two devices for the detection of obstruction. The agreement and relation between the values of FEV1 and FVC in absolute value and the FEV1/FVC ratio measured by both devices were analyzed by calculating the intraclass correlation coefficient (ICC) and the Pearson correlation coefficient (r) respectively.

RESULTS

200 patients (100 from each center) were included with a mean age of 57 (± 14) years, 110 were men (55%). Obstruction was detected by conventional spirometry in 73 patients (40.1%). Using a FEV1/FVC ratio smaller than 0.7 to detect obstruction with the Air Smart-Spirometer, the kappa index was 0.88, sensitivity (90.4%), specificity (97.2%), PPV (95.7%), NPV (93.7%), positive likelihood ratio (32.29), and negative likelihood ratio (0.10). The ICC and r between FEV1, FVC, and FEV1 / FVC ratio measured by the Air Smart Spirometer and the conventional spirometer were all higher than 0.94.

CONCLUSION

The Air-Smart Spirometer is a simple and very precise instrument for detecting obstructive airway diseases. It is easy to use, which could make it especially useful non-specialized care and in other areas.

Multicenter study of the COPD-6 screening device: feasible for early detection of chronic obstructive pulmonary disease in primary care?

Background and aim

Early detection of COPD may reduce the future burden of the disease. We aimed to investigate whether prescreening with a COPD-6 screening device (measuring FEV₁ and FEV₆) facilitates early detection of COPD in primary care.

Methods

In primary care, individuals at high risk of COPD (ie, age ≥35 years, relevant exposure, and at least one respiratory symptom) and no previous diagnosis of obstructive lung disease were examined with a COPD-6 screening device. In prioritized order, the criteria for proceeding to confirmatory spirometry were FEV₁/FEV₆ <0.7, FEV₁ <80%pred, or clinical suspicion of COPD regardless of test result (medical doctor’s [MD] decision). Based on spirometry, including bronchodilator (BD) reversibility test, individuals were classified as COPD (post-BD FEV₁/FVC <0.70), asthma (ΔFEV₁ ≥0.50 L), or no obstructive lung disease.

Results

A total of 2,990 subjects (54% men, mean age 59 years, and mean 28 pack-years) were enrolled, of whom 949 (32%) proceeded from COPD-6 screening to confirmative spirometry based on the following criteria: 510 (54%) FEV₁/FEV₆ <0.70, 382 (40%) FEV₁ <80%pred, and 57 (6%) MD decision. Following confirmative spirometry, the 949 individuals were diagnosed as having COPD (51%), asthma (3%), and no obstructive lung disease (45%). COPD was diagnosed in 487 (16%) of the enrolled subjects in whom confirmative spirometry was performed in 69% based on FEV₁/FEV₆ <0.7 and in 29% based on FEV₁ ≤80%pred.

Conclusion

Prescreening with the COPD-6 device showed acceptable specificity for the selection of subjects for diagnostic spirometry and is likely to be a useful alternative to current practice in primary care.

Diagnostic accuracy of screening tests for COPD: a systematic review and meta-analysis

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is widely underdiagnosed. A number of studies have evaluated the accuracy of screening tests for COPD, but their findings have not been formally summarised. We therefore sought to determine and compare the diagnostic accuracy of such screening tests in primary care.

METHODS

Systematic review and meta-analysis of the diagnostic accuracy of screening tests for COPD confirmed by spirometry in primary care. We searched MEDLINE, EMBASE and other bibliographic databases from 1997 to 2013 for diagnostic accuracy studies that evaluated 1 or more index tests in primary care among individuals aged ≥35 years with no prior diagnosis of COPD. Bivariate meta-analysis of sensitivity and specificity was performed where appropriate. Methodological quality was assessed independently by 2 reviewers using the QUADAS-2 tool.

RESULTS

10 studies were included. 8 assessed screening questionnaires (the COPD Diagnostic Questionnaire (CDQ) was the most evaluated, n=4), 4 assessed handheld flow meters (eg, COPD-6) and 1 assessed their combination. Among ever smokers, the CDQ (score threshold ≥19.5; n=4) had a pooled sensitivity of 64.5% (95% CI 59.9% to 68.8%) and specificity of 65.2% (52.9% to 75.8%), and handheld flow meters (n=3) had a sensitivity of 79.9% (95% CI 74.2% to 84.7%) and specificity of 84.4% (68.9% to 93.0%). Inadequate blinding between index tests and spirometry was the main risk of bias.

CONCLUSIONS

Handheld flow meters demonstrated higher test accuracy than the CDQ for COPD screening in primary care. The choice of alternative screening tests within whole screening programmes should now be fully evaluated.

PROSPERO REGISTRATION NUMBER

CRD42012002074.

Lung function testing in health and disease: issues pertaining to Asia-Pacific populations

The Asia-Pacific region comprise of diverse ethnic populations and healthcare systems of highly variable developmental stages. We face challenges in lung function testing, many of which are different from the issues encountered in the west. In some places, access to proper lung function testing facilities is very limited due to resource constraints or geographic inconvenience. It is important to note the potential differences of normative values in Asia-Pacific populations, compared with established values derived from populations of Caucasian ethnicity, hence the need to choose from available prediction formulae the ones that most closely approximate the subjects being tested. The criteria for defining abnormality is a hot topic globally. In the Asia-Pacific region, the trade-off between simplicity and thus ease of application and the pitfall of under- or over-diagnosis based on fixed cut-off values has to be recognized. The promotion of wider availability and proper utilization of lung function testing will go a long way in the enhancement of respiratory health and disease management in the region.