Using the Lower Limit of Normal Instead of the Conventional Cutoff Values to Define Predictors of Pulmonary Function Impairment in Subjects With Chronic Heart Failure.
BACKGROUND
Using the newer lower limit of normal criterion instead of the conventional cutoff values to define pulmonary function abnormalities may result in different predictors of pulmonary function impairment in patients with heart failure. Therefore, we assessed predictors of pulmonary function impairment in subjects with chronic heart failure according to the lower limit of normal in comparison with conventional cutoff values.


METHODS
In this prospective cross-sectional study, 164 chronic heart failure subjects (age 68 ± 10 y, 78% men, 88% New York Heart Association class I-II) with left ventricular ejection fraction <40% underwent pulmonary function tests. Predictors of pulmonary function impairment were assessed using the lower limit of normal and conventional cutoff values (ie, 80% predicted value and the fixed ratio of FEV1/FVC <0.7).


RESULTS
The lower limit of normal criterion identified an extra independent predictor of diffusion impairment compared with the 80% predicted value; in addition to body mass index, pack-years, and alveolar volume, female sex also turned out to be an independent predictor. A smoking history of ≥10 pack-years was a significant predictor of diffusion impairment and airway obstruction using the lower limit of normal criterion but not using the conventional cutoff values. However, lowering the cutoff points of conventional criteria to match the more stringent lower limit of normal and thus avoid overdiagnosis of diffusion impairment and airway obstruction in the elderly produced similar results as the lower limit of normal.


CONCLUSIONS
The lower limit of normal identifies more predictors of diffusion impairment and airway obstruction compared with conventional cutoff values in subjects with chronic heart failure with left ventricular systolic dysfunction. However, lowering the conventional cutoff points yielded similar results as the lower limit of normal. (ClinicalTrials.gov registration NCT01429376.).
Department of Pulmonary Diseases aminasian@rijnstate.nl.
Armine G
AG
Minasian
Department of Pulmonary Diseases.
Frank J J
FJ
van den Elshout
Department of Pulmonary Diseases, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
P N Richard
PN
Dekhuijzen
Department of Pulmonary Diseases.
Petra J E
PJ
Vos
Department of Cardiology, Rijnstate Hospital, Arnhem, The Netherlands.
Frank F
FF
Willems
Department of Cardiology, Rijnstate Hospital, Arnhem, The Netherlands.
Paul J P C
PJ
van den Bergh
Department of Pulmonary Diseases, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
Yvonne F
YF
Heijdra
D000368:Aged; D000402:Airway Obstruction / Q000175:diagnosis / Q000209:etiology; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D005260:Female; D006333:Heart Failure / Q000150:complications / Q000503:physiopathology*; D006801:Humans; D008171:Lung Diseases / Q000175:diagnosis / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012016:Reference Values; D012129:Respiratory Function Tests / Q000592:standards*; D012131:Respiratory Insufficiency / Q000175:diagnosis / Q000209:etiology*; D012307:Risk Factors; D012737:Sex Factors; D012907:Smoking / Q000009:adverse effects
Chronic heart failure; conventional cutoff values; lower limit of normal; predictors; pulmonary function impairment