Conflict of Interest. Actelion, Bohringer-Ingelheim, Bayer (Congress support and study). LFT parameters used in COPD diagnosis and their role in clinical practice: Lower Limit of Normal. Esen KIYAN, MD İ.Ü. İstanbul Medical Faculty Department of Respiratory Diseases.
Actelion, Bohringer-Ingelheim, Bayer (Congress support and study)
Esen KIYAN, MD
İ.Ü. İstanbul Medical Faculty
Department of Respiratory Diseases
LLN: statistical definition clinical practice:
Below 5th percentile of reference population (false negative rate %5)
Hankinson JL, AJRCCM 1999
Falaschetti ERJ 2004 clinical practice:
In healty people, decrease in FEV1 with age is bigger than decrease in FVC. This causes decrease in FEV1/FVC ratio by age.
Age>45, LLN for FEV1/FVC<0.70
(Falaschetti E, ERJ 2004; Stanojevic S, AJRCCM;2008; Stanojevic S, ERJ 2010)
Obstruction= FEV1/FVC<LLN (<5th percentile of predicted value, 5th percentile of healthy population)
LLN=predicted value – (1.645*SD)
Usin the lower limit of normal for the FEV1/FVC ratio reduces the misclassification of airway obstruction. Swanney Thorax 2008
40 646 adult/13 136 asymptomatic and never smoker
American (4630)-Dutch (1204)-British (7302) populations’s pirometry data
COPD prevalence in asymptomaticandneversmokeradults.HSE: HealthSurveyforEngland 1995-96, NL: Hollanda verisi, NHANES: NationalHelathandNutritionExaminationSurvey (beyaz ırk için Amerika verisi)
LLN for FEV1/FVC decreases in healthy population with age (in man 57, in women 55 prediction equations)
False COPD diagnosis in healthy adults over 60 years: %17-45 in men, %7-26 in women
Swanney Thorax 2008
Hardie JA, ERJ 2002; Celli BR, ERJ 2003; Roberts SD, Chest 2006; Vollmer WM, ERJ 2009; Swanney MP, Thorax 2008; Ko FWS, ERJ 2008; Schermer TR, ERJ 2008; Miller MR, Chesy 2010; Vaz Fragoso CA, AJRCCM 2010
FEV1/FVC and FEV1 pred values (Falaschetti adults ≥45et al.)
1995-1996 Health Surveys for England
Nonsmoker men without asthma,
At 47 age, LLN for FEV1/FVC<0.7 line (false positive)
47-49 ages LLN for FEV1>%80 pred (GOLD stage 1/milfd obst.)
Over 50, LLN for<%80 pred (GOLD stage 2/moderate obst.)
GOLD0 criteria misses COPD cases in young adults and therefore causes delay in treatment to prevent disease progression
Cerveri 2009: Age<52, true COPD diagnosis with fixed ratio is 77% in women and 57% in men.
Hansen 2007: false negative diagnosis is 50% with fixed ratio
Hoesein M, et al. Lower limit of normal or FEV1/FVC<0.70 in diagnosing COPD: An evidence-based review. Respir Med 2011.
MEDLINE, EMBASE, Cochrane data
Studies between 1966-2010
Total 1954 studies……………18 evaluated
Level of evidence (1a/b---expert opinion:5)
Hoesein M, Resp Med 2011 diagnosis?
COPD prevalence according to diagnostic criteria
>LLN but <0.70 (in-between obstruction) group had higher comorbidity-especially cardiac.
Mortality (HR 1.3) andhospitalisation (HR 2.6) higherthancaseswith normal spirometry
Fixedratiomayidentify at-risk patients. Using LLN toclassifylungdisease in olderpeoplemaymiss a part of thepopulationmorelikelytohavecomplications.
FEV1/FVC LLN Thorax 2007
FEV1/FVC LLN, FEV1<%80
LLN and FEV1<%80
Ratio and FEV1 <LLN
GOLD 2-4 prevalence
Local pred equations
COPD prevalence in never smoker healthy people
FEV1/FVC<0.70 disadvantages results from the BOLD study. Volmer WM, ERJ 2009
Underdiagnosis in young adults
Delay in treatment
Problems of LLN
1995-2004 arası yayınlanan referans denklemleri results from the BOLD study. Volmer WM, ERJ 2009
White people have at least 30 reference equations for FEV1/FVC LLN
They must be specific for countries
LLN is an statistical definition and decreases misclassifications.
Is it true to use GOLD COPD diagnosis criteri?