Table. 1—

Sensitivity(Sens), specificity (Spec) and positive predictive value (PPV) of different operational definitions of asthma, as compared with “ever asthma” and with bronchial hyperreactivity

	n	Prev %	Ever asthma			Bronchial hyperreactivity^#
	n	Prev %	Sens	Spec	PPV^¶	Sens	Spec	PPV^¶
Wheeze
Wheeze	2443	22	0.63	0.82	0.29	0.47	0.82	0.22
Wheeze, breathlessness	1209	11	0.48	0.92	0.45	0.31	0.93	0.29
Wheeze, breathlessness, no cold	808	7	0.38	0.95	0.53	0.24	0.95	0.33
Bronchial hyperresponsiveness
Slope >25%	2815	25	0.64	0.78	0.26
>20% at 1 mg	1538	14	0.52	0.90	0.38	^§	^§	^§
Slope >10%	1129	10	0.42	0.93	0.42
Wheeze and BHR^#
Wheeze, BHR	725	6.4	0.40	0.96	0.62
Wheeze, breathlessness, BHR	481	4.3	0.32	0.98	0.75	^§	^§	^§
Wheeze, breathlessness, no cold, BHR	366	3.2	0.26	0.99	0.81
ECRHS definition⁺
Any 1 of 3 variables	849	7.5				0.25	0.95	0.34
Any 2 of 3 variables	286	2.5	^§	^§	^§	0.14	0.99	0.99
All 3 variables	117	1.0				0.06	1.00	0.59
Score
Any 1 of 8 questions	3719	32.9				0.60	0.71	0.18
Any 2 of 8 questions	1679	14.9				0.40	0.89	0.27
Any 3 of 8 questions	937	8.3				0.28	0.95	0.34
Any 4 of 8 questions	538	4.8	^§	^§	^§	0.20	0.98	0.98
Any 5 of 8 questions	344	3.0				0.15	0.99	0.50
Any 6 of 8 questions	212	1.9				0.11	0.99	0.56
Any 7 of 8 questions	115	1.0				0.06	1.00	0.59
All 8 questions	43	0.4				0.02	1.00	0.63

Data are presented as n, unless otherwise stated. Prev: prevalence; BHR: bronchial hyperresponsiveness; ECRHS: European Community Respiratory Health Study. ^#: >20% fall in FEV₁ at 1 mg; ^¶: theoretical PPV, if true prevalence of asthma 10%; ⁺: woken by shortness of breath, attack of asthma or asthma medication; ^§: part of the definition.