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

• Published in: Respiratory care Vol. 61; no. 2; pp. 173 - 183
• Main Authors: Minasian, Armine G, van den Elshout, Frank J J, Dekhuijzen, P N Richard, Vos, Petra J E, Willems, Frank F, van den Bergh, Paul J P C, Heijdra, Yvonne F
• Format: Journal Article
• Language: English
• Published: United States Daedalus Enterprises, Inc 01-02-2016
• Subjects: Aged; Airway Obstruction - diagnosis; Airway Obstruction - etiology; Analysis; Body Mass Index; Cardiac patients; Care and treatment; Complications and side effects; Cross-Sectional Studies; Female; Heart failure; Heart Failure - complications; Heart Failure - physiopathology; Humans; Lung diseases; Lung Diseases - diagnosis; Lung Diseases - etiology; Male; Middle Aged; Predictive Value of Tests; Prospective Studies; Reference Values; Respiratory Function Tests - standards; Respiratory Insufficiency - diagnosis; Respiratory Insufficiency - etiology; Risk Factors; Sex Factors; Smoking - adverse effects; United States; predictors; conventional cutoff values; lower limit of normal; Chronic heart failure; pulmonary function impairment
• ISSN: 0020-1324; 1943-3654
• DOI: 10.4187/respcare.04101

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.
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).
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.
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.).