. 2023 Apr 20;10(1):e001478. doi: 10.1136/bmjresp-2022-001478

Table 1.

Undiagnosed clinical COPD* and its overdiagnosis using postbronchodilator spirometry: cross-sectional studies of symptomatic adults or adults taking inhaler therapies in primary healthcare settings

Author year citation	Study name location	Participant no† (%eligible‡), Sampling, selection, no/type of GP practices	Gender Age (mean (SD) years)	Prevalence of spirometry-defined COPD (%, (n/N))§	Underdiagnosis in COPD subpopulation (%, (n/N))§	Undiagnosed COPD in studied population (%, (n/N))*§	Overdiagnosis in population labelled with COPD (%, (n/N))§
Smokers with symptoms
Liang, 2018²⁹	RADICALS study Australia	N=1050 (9.8%) Consecutive; adults >40 years, symptomatic ever-smokers with ≥2 GP visits in last 12 months; 43 urban practices	60%–63% male Undiagnosed: 62 (10) years Diagnosed: 67(10) years	25.9% (272/1050)	52.2% (142/272)	13.5% (142/1050)**	41.2% (91/221)**
Løkke, 2012³⁷	Denmark, Sweden	N=4049 (n/a) Adults ≥35 years Ever-smoker or occupational exposure plus ≥1 respiratory symptom No previous lung disease; 241 GPs	51% male 58 (male) 57 (female)	21.7% (878/4049) excluding BDR>500 mL	¶	21.7% (878/4049)	NA
Sandelowsky, 2011⁴⁰	Stockholm, Sweden	N=138 (69.7%)† Adults 40–75 years Ever-smoker (current or past) with an LRTI, without prior lung disease No of suburban clinics unclear	44% male 55 years (95% CI 54 to 57)	27.5% (38/138) spirometry 4–5 weeks post-LRTI	¶	27.5% (38/138)	NA
Yawn, 2009⁴³	USA	N=1201 (93.6%) Non-consecutive; adults >40 years Chronic bronchitis and >10 pack-years without inhaler use or COPD confirmed by spirometry; 50 practices	45% male 52.9 (9.1) years 80% white	25.6% (308/1201)	¶**	25.6% (308/1201)	NA
Inhalers including asthma
Abramson, 2012³⁵	SPIRO-GP, VIC Australia, prior to randomisation	N=199 (12.1%) Adults 18–70 years Prescribed inhaled medication from 31 urban GP practices	33% males 54 (13) years	45.7% (91/199) (COPD+ACO)	58.2% (53/91)** (COPD+ACO)	26.6% (53/199)** (COPD+ACO)	32.1% (18/56)** (COPD+ACO)
Tinkelman, 2006⁴⁸	Aberdeen UK, Denver, USA	N=597 (1–10%)‡ Representative; adults ≥40 years with history of OLD and/or receipt of inhalers last 12 months Query no of GP practices	38.3% male 58.7 (11) years	39.4% (235/597) (COPD+ACO) 28.6% (171/597) (COPD only)	62.1% (146/235) (COPD+ACO) 68.4% (117/171) (COPD only)	24.5% (146/597) (COPD+ACO) 19.6% (117/597) (COPD only)	51.6% (95/184) (COPD+ACO) 60.6% (83/137) (COPD only)
Symptoms-risk factors
Frank, 2006⁴⁶	MAGIC study, Manchester, UK	N=825 (≈14%) Consecutive; adults ≥30 years Ever-smokers and/or ≥4 symptoms or risk factors ††; 2 GP practices	45.3% male 55.5 years	19.8% (163/825) (GOLD stage II–IV)	63.2% (103/163)	12.5% (103/825)**	NA
Hamers, 2006⁴⁷	Brazil	N=142 (40.6%)† ≥15 years old with symptoms of shortness of breath and/or cough 34 urban and rural GP practices	45.1% male 46.8 (18.7) years	25.4% (36/142)	75% (27/36)	19.0% (27/142)**	70% (21/30)**

*Clinical COPD if patient subjects had symptoms and spirometric evidence of COPD; undiagnosed based on an absent diagnosis in medical records except for Tinkelman et al.⁴⁸

†COPD prevalence could be inaccurate due to insufficient sample size (online supplemental results E4), so have been omitted from the forest plots in a sensitivity analysis.

‡All % eligible figures were calculated, except when mentioned in the discussion text by Tinkelman et al.⁴⁸

§COPD was defined using the GOLD criterion, postbronchodilator forced expiratory ratio <0.70, except where indicated by § when the only criterion was the LLN.

¶Percentage undiagnosed in the COPD subpopulation was 100% as the population excluded patients with a history of COPD (3 of total of 7 studies).

**Data needed to be deduced and calculated from the figures given (by the present authors).

††Includes wheezing; woken by cough, chest tightness, dyspnoea; hay fever or familial asthma.⁴⁸

ACO, asthma-COPD overlap; BDR, bronchodilator response; COPD, Chronic obstructive pulmonary disease; GOLD, Global Initiative for Chronic Obstructive Lung Disease; GP, general practitioner; LLN, lower limit of statistical normal; LRTI, lower respiratory tract infection; NA, not available; OLDs, obstructive lung diseases; PC, primary care.