title: The FEV1/FEV6 ratio is a good substitute for the FEV1/FVC ratio in the elderly.
abstract: OBJECTIVE
  To determine the agreement between the FEV1/FEV6 ratio and the FEV1/FVC ratio in an elderly population.
  
  
  METHODS
  The study sample consisted of 3874 participants in a cross-sectional population survey in Tromsö, Norway, aged 60 years or more, in whom acceptable spirometry had been obtained. Mean differences between the FEV1/FEV6 ratio (%) and the FEV1/FVC ratio (%) were calculated according to age, sex, smoking habit, and the degree of airflow limitation. ROC-curve analysis and Kappa-statistics were used to estimate the utility of the FEV1/FEV6 ratio in predicting an FEV1/FVC ratio < 70%.
  
  
  RESULTS
  The mean difference between FEV1/FEV6% and FEV1/FVC% was 2.7% in both men and women. The difference between the two measures increased somewhat with increasing age, and was more pronounced with smoking and decreasing FEV1/FVC ratio. The value for the FEV1/FEV6 ratio which best predicted an FEV1/FVC ratio of 70%, was 73%, and a very good agreement was found between these two cut-off values (kappa = 0.86).
  
  
  CONCLUSIONS
  The FEV1/FEV6 ratio appears to be a good substitute for the FEV1/FVC ratio in an elderly population.
authors.affiliation: Institute of Community Medicine, University of Tromsø, 9037 Tromsø, Norway. hasse.melbye@ism.uit.no
authors.forename: Hasse
authors.initials: H
authors.lastname: Melbye
authors.forename: Astri
authors.initials: A
authors.lastname: Medbø
authors.forename: Alan
authors.initials: A
authors.lastname: Crockett
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D008875:Middle Aged; D009664:Norway; D012372:ROC Curve; D012907:Smoking / Q000009:adverse effects; D013147:Spirometry / Q000295:instrumentation / Q000379:methods*; D011795:Surveys and Questionnaires