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

Abstract

Background: 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. Objectives: 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). Methods: 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. Results: 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). Conclusions: 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.

Assessment of comorbidities and prognosis in patients with COPD diagnosed with the fixed ratio and the lower limit of normal: a systematic review and meta-analysis

“…Of the final 13 studies, 11 were cohort studies and 2 were cross-sectional studies. According to the quality assessment, 11 cohort studies were rated high; 6 studies [ 17 , 21 , 22 , 24 , 29 , 31 ] scored 9/9 stars, 3 [ 25 , 26 , 30 ] scored 8/9, and 2 [ 20 , 27 ] scored 7/9 according to the NOS criteria. The 2 cross-sectional studies scored high on the methodological quality evaluation with one [ 28 ] scoring 8 and the other [ 23 ] scoring 10 on the AHRQ scale (Supplementary S1, S2).…”

“…Two researchers (S.T.K and Z.L) independently reviewed the full text of 90 potentially eligible studies. Finally, 13 studies [17,[20][21][22][23][24][25][26][27][28][29][30][31] and 154,447 participants were included in the meta-analysis ( Fig. 1).…”

Causal Effects of Body Mass Index on Airflow Obstruction and Forced Mid-Expiratory Flow: A Mendelian Randomization Study Taking Interactions and Age-Specific Instruments Into Consideration Toward a Life Course Perspective

“…Third , age-related changes in inflammation, immunologic responses and mechanical lung properties could alter the susceptibility of the airways to obesity ( 61 ). Challenges in interpreting low FEV1/FVC in the elderly have been discussed ( 62 ). Fourth , the observed age-interaction could in part be explained by survivor bias, if survivors with high BMI are those most resistant to the adverse LF effects of obesity.…”

Mortalitätsrisiko von älteren Menschen mit Bronchialobstruktion - die prognostische Relevanz von Grenzwerten

“…Pedone et al [8] untersuchten in ihrer Analyse der Daten der SaRA-Studie (Salute Respiratoria nell'Anziano, italienisch für Atemwegsgesundheit im Alter) den Einfluss der Verwendung eines fixen Grenzwertes von <70% für die relative Einsekundenkapazität mit einem LLN-Wert, welcher nach einer aktuellen Formel mit einer Gültigkeit für Menschen bis zum 90. Lebensjahr berechnet wurde [5], auf die Mortalität von Menschen mit Bronchialobstruktion über einen Zeitraum von 15 Jahren.…”