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Respiration. 2017;94(5):424-430. doi: 10.1159/000479285. Epub 2017 Sep 8.

Difference in Mortality Risk in Elderly People with Bronchial Obstruction Diagnosed Using a Fixed Cutoff or the Lower Limit of Normal of the FEV1/FVC Ratio.

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Area di Geriatria, Università Campus Biomedico di Roma, Rome, Italy.



Whether a fixed cutoff or the lower limit of normal of the FEV1/FVC ratio should be used to diagnose bronchial obstruction is still a matter of debate. This issue is particularly important for elderly people.


We used equations applicable up to 90 years of age to evaluate the mortality of elderly people diagnosed with bronchial obstruction using either a fixed cutoff of 0.7 or the lower limit of normal (LLN).


Participants in the SaRA (Salute Respiratoria nell'Anziano, Italian for "Respiratory Health in the Elderly") study were grouped as follows: FEV1/FVC ≥0.7 and ≥ LLN (n = 535: F-/L-), FEV1/FVC <0.7 but ≥ LLN (n = 118: F+/L-), and FEV1/FVC <0.7 and < LLN (n = 229: F+/L+). We estimated the mortality risk in the three groups over 15 years of follow-up.


The mean age was 73 years (58% men). The hazard ratio (HR) for mortality was 1.427 (95% CI: 1.09-1.868) in the F+/L- group and 2.143 (95% CI: 1.13-1.995) in the F+/L+ group. After adjustment for potential confounders, we found no increased mortality in the F+/L- group (HR: 1.007, 95% CI: 0.755-1.342), while the HR in the F+/L+ group was still sizeable (1.474, 95% CI: 1.136-1.911).


As expected, using a fixed cutoff translates in a larger number of people to be classified as having bronchial obstruction. In our sample the increased mortality in the F+/L- group is due to the confounding effect of age and sex. Our study lends support to the use of LLN in elderly people.


Bronchial obstruction; Elderly; Fixed cutoff; Lower limit of normal

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