Table 2. Studies evaluating spirometry, screening questionnaires and handheld flow meters.
| Characteristic |
Range (no. of studies) |
|||
|---|---|---|---|---|
| Diagnostic spirometry (n=30) | Screening questionnaires (n=13) | Handheld flow meters (n=5) | ||
| Study designs | RCT | 1 | 1 | 0 |
| Cluster RCT | 0 | 1 | 0 | |
| Non-randomised trial | 1 | 0 | 0 | |
| Test accuracy study | 7 | 8 | 4 | |
| Single-arm study | 21 | 3 | 1 | |
| Participantsa | Screened | — | 18,932 | 4,759 |
| Performed spirometry | 63,087 | 8,845 | 568 | |
| Diagnosed with COPD | 10,428 | 1,996 | 346 | |
| Mean age (years) | 47.9–65.3 | 52.3–65.3 | 52–65 | |
| Male (%) | 19.6–100 | 38.1–69 | 37.7–99.7 | |
| Required smoking status | Current/ex-smokers | 11 | 7 | 2 |
| Inc. never smokers | 19 | 6 | 3 | |
| Required respiratory symptoms | 5 | 0 | 0 | |
| Setting | General practice(s) | 24 | 12 | 5 |
| Pharmacies | 1 | 1 | 0 | |
| Other | 3 | 0 | 0 | |
| Not reported | 2 | 0 | 0 | |
| Number of centres | 1–821 | 1–36 | 3–25 | |
| Multicentre | 24 | 12 | 5 | |
| Single centre | 2 | 1 | 0 | |
| Not reported | 4 | 0 | 0 | |
| Recruitment strategy | Active | 13 | 6 | 1 |
| Opportunistic | 14 | 4 | 3 | |
| Active and opportunistic | 1 | 2 | 1 | |
| Not reported | 2 | 1 | 0 | |
| Questionnaires | CDQ1 | — | 6 | — |
| LFQ | — | 2 | — | |
| Not named | — | 5 | — | |
| Common items | — | — | ||
| Age | — | 11 | — | |
| Smoking status | — | 12 | — | |
| Respiratory symptoms | — | 13 | — | |
| Allergies | — | 7 | — | |
|
Handheld spirometers | ||||
| Device | Piko-6 | — | — | 4 |
| COPD-6 | — | — | 1 | |
| Operator | Nurse | — | — | 3 |
| GP | — | — | 1 | |
| Not reported | — | — | 1 | |
| Use of bronchodilator | Pre-bronchodilator | — | — | 3 |
| Post-bronchodilator | — | — | 2 | |
| Test threshold | FEV1/FEV6<0.7 | — | — | 3 |
| FEV1/FEV6<0.75 | — | — | 1 | |
| FEV1/FEV6<0.8 | — | — | 1 | |
|
Spirometry | ||||
| Post-bronchodilator | 15 | 10 | 5 | |
| Pre-bronchodilator | 13 | 3 | 0 | |
| Not reported | 2 | 0 | 0 | |
| Definition of airflow obstruction | Post-BD FEV1/FVC<0.7 | 12 | 9 | 3 |
| Pre-BD FEV1/FVC<0.7 | 9 | 2 | 0 | |
| Post-BD FEV1/FVC<LLN | 1 | 0 | 0 | |
| Pre-BD FEV1/FVC<LLN | 1 | 0 | 0 | |
| Other | 7 | 2 | 2 | |
| Symptoms in definition of COPD | 4 | 3 | 0 | |
| Spirometry quality control | Yes | 22 | 11 | 2 |
| No | 4 | 2 | 1 | |
| Unclear | 4 | 0 | 2 | |
|
Range of results | ||||
| New COPD cases/eligible subjectsa | 1.7–30.5%19 | 0.4–22.3%8 | 6–20%3 | |
| New COPD cases/no. screened | — | 1.5–30.0%12 | 3–20%5 | |
| New COPD cases /no. assessed with spirometry | 4.1–40.2%30 | 14.3–42.1%13 | 19–94%5 | |
| Severity of new cases (FEV1% predicted)b | ⩾80% | 11.5–86.7% | 11.5–51.1% | 33.3–64.3% |
| 50–80% | 12.9–68.2% | 42.8–87.5% | 35.7–61.4% | |
| <50% | 0–37.2% | 5.3–37.2% | 0–16.2% | |
Abbreviations: BD, bronchodilator; CDQ, COPD Diagnostic Questionnaire (also referred to as the Respiratory Health Screening Questionnaire and the International Primary Airways Group Questionnaire); COPD, chronic obstructive pulmonary disease; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; LFQ, Lung Function Questionnaire; LLN, lower limit of normal; RCT, randomised controlled trial.
a
A number of studies did not report the total eligible population.
b
Restricted to studies that reported severity staging according to the Global Initiative for Obstructive Lung Disease (GOLD) strategy.16