Table 1.
Characteristics of studies included in the meta-analysis.
| Author and year | Country | Setting | Study designs | Portable spirometer | Test threshold of portable spirometers | Definition of airflow obstruction | Portable spirometers operator | Inclusion and exclusion criteria | Sample size (male) | Age (years, mean ±SD) |
|---|---|---|---|---|---|---|---|---|---|---|
| Chen G 201810 | China | 1 tertiary hospital | randomized | IQ-spiro |
Cut-off value unclear-FEV1/FEV6<0.74 |
post-FEV1/FVC<0.70 | Professional technician | Subjects who visited a tertiary hospital | 159 (-) | 55±14.7 |
| Chen S 202137 | China | 8 primary cares | cross-sectional study | COPD-6 |
Cut-off value unclear-FEV1/FVC<0.77 |
post-FEV1/FVC<0.70 | Trained physician | Aged ≧ 40 years | 1487 (-) | - |
| Dickens AP 202038 | UK | 71 general practices | case-control | COPD-6 |
Cut-off value Pre-FEV1/FEV6<0.78 |
post-FEV1/FVC<LLN | Trained research assistants | aged≧40, who either had previously clinically diagnosed COPD or had reported chronic respiratory symptoms. | 544 (349) | 69.6±9.1 |
| Figueira Goncalves JM 201739 | Spain | 1 tertiary hospital | cross-sectional observational study | COPD-6 |
Cut-off value Pre-FEV1/FEV6<0.75 |
pre-FEV1/FVC<0.70 | Professional technician | patients referred to laboratory for respiratory functional tests | 233 (133) | 59±15 |
| Frith P 201140 | Australia | 4 primary care practices | prospective, multicenter | PiKo-6 |
Cut-off value preFEV1/FEV6<0.75 |
post-FEV1/FVC<0.70 | Trained nurse or general practitioner (GP) | current or former smokers, aged > 50 years, no previous diagnosis of obstructive lung disease, and no treatment for obstructive lung disease in the past year. | 204 (69) | 61±8 |
| Frith P 2011*40 | Australia | 4 primary care practices | prospective, multicenter | PiKo-6 |
Cut-off value Pre-FEV1/FEV6<0.75 |
post-FEV1/FVC<0.70 | Trained nurse or general practitioner (GP) | current and former smokers aged >50 years, a previous diagnosis of or treatment for asthma, and no previous diagnosis of COPD. | 93 (54) | 62±8.8 |
| Hidalgo Sierra V 201841 | Spain | 2 primary care centers* | - | PiKo-6 |
Cut-off value unclear-FEV1/FEV6≦0.70 |
post-FEV1/FVC<0.70 | Professional technician* | aged ≧40 years, a pack-year index (PYI)≧10, and typical symptoms, such as cough, expectoration and dyspnea, and with no previous diagnosis of COPD | 155 (111) | 63±14 |
| Hwang YI 202142 | Korea | 5 tertiary hospitals | - | COPD-6 |
Cut-off value pre-FEV1/FEV6<0.73 |
post-FEV1/FVC<0.70 | Professional technician |
Aged ≧ 40 years; respiratory symptoms and PYI≧10 pack-years. Subjects who had a history of disease such as tuberculous sequalae, bronchiectasis, asthma, and lung cancer that might influence pulmonary function tests were excluded. |
290 (-) | 63.1 ± 11.0 |
| Kim JK 201643 | Korea | 9 primary clinics | prospective cohort study | COPD-6 |
Cut-off value preFEV1/FEV6≦0.77 |
post-FEV1/FVC<0.70 | primary care physicians |
Subjects who visited a primary clinic complaining of respiratory symptoms and aged ≧40 years, PYI≧10 irrespective of their current smoking state and had no previous diagnosis of COPD. Patients with a history of disease that might have influenced spirometry results, such as tuberculosis-destroyed lungs, bronchiectasis, asthma, or lung cancer were excluded. |
190 (-) | 60.3±10.6 |
| Kobayashi S 201744 | Japan | 16 primary care clinics and 4 hospitals | prospective multi-center, observational study | Hi-Checker | Fixed value unclear-FEV1/FEV6≦0.75 | post-FEV1/FVC<0.70 | primary care physicians | Patients > 40 years of age who received outpatient care for chronic disease at primary care clinics Patients with known chronic respiratory diseases, including asthma and COPD, and patients suffering from acute respiratory symptoms were excluded. | 110 (91) | 68.5±0.8 |
| Labor M 20169 | Croatia | 26 general practitioners’ office | prospective cohort study | COPD-6 |
Cut-off value unclear-FEV1/FEV6≦0.78 |
post-FEV1/FVC<0.70 | Trained GPs |
written consent. aged 40–65 years with a smoking history of PYI≧2; with no previous diagnosis of COPD. |
227 (112) | 52.5±6.8 |
| Li XF 202045 | China | 1 district hospitals and ten primary care centers. | - | SP10BT | Cut-off value post-FEV1/FVC<0.7 and FVC>80%pred | post-FEV1/FVC<0.70 and FVC<80%pred | 2 trained primary care physicians | aged > 40 years, typical symptoms such as chronic cough expectoration, or asthma, and risk factor exposure history | 252 (182) | 65.7±10.1 |
| Lin CH 202146 | Taiwan, China | 26 outpatient clinics | prospective multi-center, | Spirobank Smart | Cut-off value pre-FEV1/FVC<0.74 | post-FEV1/FVC<0.70 | trained nurses and physicians | Aged ≧ 40 years, PYI≧10 pack-years., with chronic respiratory disease and no previous diagnosis of COPD. | 370 (349) | 60.9±9.7 |
| Llordes M 201747 | Spain | 8 primary care centers | - | COPD-6 | Cut-off value unclear-FEV1/FEV6≦0.78 | post-FEV1/FVC<0.70 | Trained primary care physician, a nurse or a technician | Aged ≧ 40 years with a smoking history of PYI≧1; with no previous diagnosis of COPD and attended the primary care centers for any reason | 407 (265) | 57.4±8.9 |
| Mahboub B 201422 | United Arab Emirates | 5 primary cares, 2 large shopping malls and 1 industrial city | cross sectional study | PEF |
Fixed value Pre-PEF<2.2L(s*m2) |
pre-FEV1/FVC<0.70 | Trained primary care physicians or nurses | Aged ≧ 40 years | 525 (358) | 49.6±4.1 |
| Ng, S. C. 201748 | Malaysia | Medical Outpatient Department and health care clinics | cross-sectional study | COPD-6 | Cut-off value post-FEV1/FEV6<0.75 | post-FEV1/FVC<0.70 | Trained stuff | Aged ≧50 years; history of dyspnoea; history of chronic cough or chronic sputum production; history of exposure to risk factors; and any smoker even in the absence of above symptoms. | 117(101) | 67.38±11.58 |
| Nishimura K 201149 | Japan | 1 tertiary hospital | - | Hi-Checker | Cut-off value unclear-FEV1/FEV6<0.746 | post-FEV1/FVC<0.70 | Professional technician | industrial workers who underwent annual health checks | 312 (312) | 55±9.4 |
| Represas CR 201050 | Spain | 1 tertiary hospital | prospective, descriptive transversal study | COPD-6 | Cut-off value unclear-FEV1/FEV6<0.77 | unclear-FEV1/FVC<0.70 | Professional technician | those who attended pulmonary function laboratory for functional respiratory tests | 162 (95) | 56±16 |
| Represas-Represas C 201651 | Spain | 8 primary care centers, 15 community pharmacies and 4 emergency services | prospective, multi-cohort study | COPD-6 | Cut-off value preFEV1/FEV6<0.80 | post-FEV1/FVC<0.70 | Trained primary care physicians or nurses |
Aged ≧40 years, with a smoking history of PYI≧10, and symptoms suggestive of COPD. Individuals who had already been diagnosed with a respiratory disease were excluded. |
362 (224) | 55.4±9.9 |
| Ronaldson SJ 201823 | UK | general practices | prospective case-finding stud | PEF |
Fixed value Pre-PEF<80%pred |
post-FEV1/FVC<0.70 and FEV1%<80%pred or FEV1%>80%pred with at least 1 symptom | Trained nurses in primary care | aged≧35; current smokers, including those who had comorbidities, such as COPD or asthma | 216 (109) | 53.4±11.0 |
| Ronaldson SJ 2018*23 | UK | general practice | prospective case-finding stud | MS01 Micro spirometer |
Fixed value FEV1/FVC<0.7, FEV1<80%pred, or FVC<80%pred |
post-FEV1/FVC<0.70 and FEV1%<80%pred or FEV1%>80%pred with at least 1 symptom | Trained nurses in primary care | aged≧35; current smokers, including those who had comorbidities, such as COPD or asthma | 216 (109) | 53.4±11.0 |
| Sami R 202052 | Iran | 1 tertiary hospital | cross-sectional descriptive study | COPD-6 | Cut-off value post-FEV1/FVC<0.72 | post-FEV1/FVC<0.70 | Professional technician |
Aged ≧ 40 years; PYI≧10 pack-years; symptoms suggestive of COPD. Patients with previously diagnosed respiratory diseases were excluded. |
122 (-) | 53.2±9.0 |
| Schneider A 200953 | Germany | 10 primary care centers | cross-sectional study | Medikro SpiroStar | Fixed value post-FEV1/FVC<0.70and FVC>80%pred | post-FEV1/FVC≦0.70 and/or FEV1<80%pred | Trained primary care physicians and practice assistants | Complaints suggestive of obstructive airway disease (OAD), had not been diagnosed previously for OAD and had not received any previous anti-obstructive medicine. | 219 (92) | 43.8±15.6 |
| Sichletidis L 201154 | Greece | Two Primary cares Centers | - | PiKo-6 | Fixed value post-FEV1/FEV6<0.70 and/or FEV1<80% | post-FEV1/FVC<0.70 | Trained primary care general practitioners |
Aged >40years. Medically confirmed diagnosis of an obstructive lung disease (e.g. COPD, asthma, bronchiectasis) and any other pulmonary disease (e.g. tuberculosis, interstitial lung disease, lung cancer), thoracic surgery in the previous 6 months or acute respiratory infection were excluded. |
1078 (616) | 65.3±11.4 |
| Thorat YT 201724 | India | Specialized Hospital | cross-sectional study | PEF | Cut-off value pre-PEF<80%pred | post-FEV1/FVC<0.70 | Professional technician |
Adult patients with respiratory complains. Patients with history of pulmonary tuberculosis, and those with contra-indications for spirometry, and also pregnant and nursing mothers were excluded. |
189 (111) | 51±17 |
| Thorat YT 2017*24 | India | Specialized Hospital | cross-sectional study | COPD-6 | Cut-off value preFEV1/FEV6<0.75 | post-FEV1/FVC<0.70 | Professional technician |
Adult patients with respiratory complains. Patients with history of pulmonary tuberculosis, and those with contra-indications for spirometry, and also pregnant and nursing mothers were excluded. |
189 (111) | 51±17 |
| Thorn J 201255 | Sweden | Twenty-one urban and rural Primary cares Centers | - | COPD-6 | Cut-off value preFEV1/FEV6<0.73 | post-FEV1/FVC<0.70 | Trained nurse | Aged 45–85 years; with a smoking history of at least 15 pack-years | 305 (132) | 61.2±8.4 |
| Tian J 201225 | China | Community settings | cluster Sampling; Prospective study | PEF | Fixed value pre-PEF<80%pred | post-FEV1/FVC<0.70 | Trained primary care physicians or nurses | Aged ≧40years | 3379 (1400) | - |
| Toda R 200956 | Japan | 1 tertiary hospital | - | PiKo-6 | Cut-off value pre-FEV1/FEV6<0.749 | pre-FEV1/FVC<0.70 | Professional technician | subjects including non-smokers, smokers, COPD, bronchial asthma, and interstitial lung diseases. | 768 (402) | 57.8±0.6 |
| van den Bemt L201457 | Nether lands. | several sites for general practitioners | randomized cross-sectional diagnostic study | PiKo-6 | Fixed value pre-FEV1/FEV6<0.73 | post-FEV1/FVC<0.70 | Trained primary care physicians | Aged ≧50 years; current or former smokers (⩾1 pack year) with no previous diagnosis of COPD | 104 (62) | - |
| Wang XY 201858 | China | 1 community | - | COPD-6 | Fixed value pre-FEV1/FEV6<0.70 | post-FEV1/FVC<0.70 | Trained technician | Aged 40-75 years | 475 (134) | 57.78±9.18 |
*In this study, both portable spirometers and traditional laboratory PFT were conducted by the high-resource medical institutions.
COPD, chronic obstructive pulmonary disease; FEV1,forced expiratory volume in 1 s; FEV6, forced expiratory volume in 6 s; FVC, forced vital capacity; GP, general practitioner; PYI, pack year index; SD, Standard Deviation.