Table 1 Characteristics of studies included in the meta-analysis.

From: Accuracy of portable spirometers in the diagnosis of chronic obstructive pulmonary disease A 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

aged40, 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/FEV60.70

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 PYI10 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/FEV60.77

post-FEV1/FVC<0.70

primary care physicians

Subjects who visited a primary clinic complaining of respiratory symptoms and aged 40 years, PYI10 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/FEV60.75

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/FEV60.78

post-FEV1/FVC<0.70

Trained GPs

written consent.

aged 40–65 years with a smoking history of PYI2; 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, PYI10 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/FEV60.78

post-FEV1/FVC<0.70

Trained primary care physician, a nurse or a technician

Aged 40 years with a smoking history of PYI1; 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 PYI10, 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

aged35; 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

aged35; 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; PYI10 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/FVC0.70 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

  1. *In this study, both portable spirometers and traditional laboratory PFT were conducted by the high-resource medical institutions.
  2. 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.