1
DIAGNOSTIC VALUE OF THE FEV1/FEV6
TO DETECT AIRWAY OBSTRUCTION
Gaye Ulubay, Nursel Türkoğlu, Sevinç S. Ulaşlı, Şule Akçay, Füsun Ö. Eyüboğlu
Baskent University Department of Pulmonary Baskent University Department of Pulmonary Diseases, AnkaraDiseases, Ankara
2
FEV1/FEV6 was found to be an accurate and
reliable alternative for the FEV1/FVC for
diagnosing airway obstruction.
Enright et al. Res Med, 2002;96:444-449.
Swanney et al. AJRCCM 2000;162-917-919
ERS monograph, 2005;1-11
Vandevoorde et al. Chest 2005;127:1560-1564
3
WHY FEV6 ?
Easier for older patients and those with severe respiratory diseases.
FEV6 is more reproducible than FVC.
Shorter maneuvers reduce the risk of syncope.
In some studies specificity was close to FVC.
Ferguson et al. Chest 2000;117:1146-1161
Swanney et al. AJRCCM 2000;162-917-919
Vandevoorde et al. Chest 2005;127:1560-1564.
4
PURPOSE
Evaluation of the relationship between
FEV1/FVC and FEV1/FEV6 in diagnosis of
airway obstruction.
5
MATERIALS AND METHODS-1
The pulmonary function tests ( PFT ) results of all 1509 subjects tested between 2003-2005, were retrospectively analyzed.
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Indications
Accurate diagnosis
Smoking status
were ignored.
MATERIALS AND METHODS-2
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Exclusion Criteria
Subjects with no cooperation
< 10 years old and >80 years old
were excluded from study.
Recent test results were taken from the subjects with repeated tests.
8
FVC maneuver was performed in accordance with ERS (European Respiratory Society) criteria.
ERS 1993 update. Eur Respir J. 1993;6(suppl 16):5-40.
9
Airway obstruction was defined as FEV1/ FVC < 70%.
Classification of level of airway obstruction according to ERS.
Siafakas et al, ERJ 1995,8:1398-1420
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Statistical Methods
All analyses were performed using SPSS software
(Statistical Package for the Social Sciences, version
9.05, SSPS Inc, Chicago, Ill, USA).
Lineer Regression Analysis
Spearman’s Correlation Analysis
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RESULTS
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Subject Demographics
n
Age
Mean ± SD
(yr)
Height
Mean ± SD
(cm)
Female 695 55 ± 18 158 ± 7
Male 814 53 ± 19 170 ± 11
Total 1509 53 ± 18 165 ± 11
13
female
male
Obstrüksiyon Yok
Obstrüksiyon Var
%
80706050403020
n=495
n=497
n=200
n=317
obstruction
no obstruction
14
No obstruction
n=992
Obstruction
n= 517
Mild Moderate Severe
Female 495 109 60 31
Male 497 110 105 102
TOTAL 992 219 165 133
15
Distribution of the Subjects According to Severity of the Airway Disease
No obstruction
Mild
ModerateSevere
Mild = FEV1 70 %
Moderate = 50 % ≤-FEV1 < 70 %
Severe = FEV1 < 50 %
65%15%
11%9%
16
• I=10-20yr
• II=21-40yr
• III=41-60yr
• IV=> 60yrDEKATLARA GÖRE DAĞILIM
4,003,002,001,00
YÜ
ZD
E
70
60
50
40
30
20
10
0
FEV1> %80
FEV1< %30
DECADES
80%
30%
P ER
CE
NT
I
No obstruction
Obstruction
II III IV
17Whole group P 0.0001, r = 0.979, r2 = 0.954
40 60 80 100
FEV1/FEV6
25
50
75
100
18
FEV1/ FVC = [ FEV1/ FEV6 x 1,17 ]-15,16
19
In subjects with airway obstruction FEV1/FEV6
specificity 100 %
sensitivity 78.3 %
positive predictive value 100 %
negative predictive value 90 %
20
FEV1/FEV6 did not detect obstruction in 10% of
cases with FEV1/FVC< 70 .
21
Degree of Airway Obstruction
r r2
Mild (FEV1 70%)
(n=219 M/F= 110/109)
0.812 0.659
Moderate (50% ≤ FEV1< 70%)
(n=165 M/F= 105/60)
0.888 0.788
Severe (FEV1 < 50 %)
(n=133 M/F= 102/31)
0.936 0.876
FEV1/FEV6 and Degree of Obstruction
22
When FEV1 decreased, rate of detected
obstruction with FEV1/FEV6 increased.
23
This result was attributed to unexpired volume
at sixth second in severely obstructed subjects.
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r r2
FEV1/FVC >70 0.959 0.920
FEV1/FVC <70 0.934 0.873
FEV1/FEV6
25
Age group r r2
•10-20yr 0.997 0.993
• 21-40yr 0.991 0.982
•41-60yr 0.969 0.939
•> 60yr 0.974 0.948
Detecting airway obstruction with FEV1/FEV6 was not affected by age.
P> 0.05
FEV1/FEV6 according to age distribution
26
DISCUSSION
27
Specificity of FEV1/FEV6 in our study was similar with
other studies but sensitivity was lower than other studies.
FEV1/FEV6 may be used in detecting airway obstruction
in general population.
Swanney et al. AJRCCM 2000;162-917-919Vandevoorde et al. Chest 2005;127:1560-1564.Demir T. et al Res Med, 2005:99;103-106Akpınar M et al. ERJ, 2006:27;374-377.
28
Lower sensitivity of FEV1/FEV6 in our study may be
due to different numbers and distribution of
obstructed subjects in other studies.
29
% 100%78.3% 34 (n=517)1509Ulubay et al.
% 98% 92% 14 (n= 165) 1143Akpınar et al.
% 100% 86.09% 62 (n= 3186)5114Demir et al.
11676
337
n
% 93.1% 94% 40 (n= 4613)Vandevoorde et al.
% 97.4% 95% 65 (n= 219)Swanney et al.
SpecificitySensitivityObstruction %
30
No difference among age decades in detecting
airway obstruction was found.
Therefore FEV1/FEV6 may be used in all subjects
between 10-80 yrs old.
31
Underestimation of obstruction with FEV1/FEV6 in 10% of cases.
Disadvantage of FEV1/FEV6 .
32
CONCLUSION
33
FEV1/FEV6 use could be appropriate in primary care and field studies as a screening test.
