Predictive Value of Different Expressions of Forced Expiratory Volume in 1 Second (FEV1) for Adverse Outcomes in a Cohort of Adults Aged 80 and Older

Abstract

Objectives: Forced expiratory volume in 1 second (FEV₁) is proposed as a marker of healthy ageing and FEV₁ expressions that are independent of reference values have been reported to be better at predicting mortality in older adults. We assess and compare the predictive value of different FEV₁ expressions for mortality, hospitalization, and physical and mental decline in adults aged 80 and older.

Design: Population-based, prospective, cohort study.

Setting: The BELFRAIL study, Belgium.

Participants: A total of 501 community-dwelling adults aged 80 and older (mean age 84.7 years).

Measurements: Baseline FEV₁ expressed as percent predicted (FEV₁PP) and z-score (FEV₁Z) using the Global Lung Function Initiative 2012 reference values; over lowest sex-specific percentile (FEV₁Q), and height squared (FEV₁/Ht²) and cubed (FEV₁/Ht³). Mortality data until 5.1 ± 0.2 years from baseline; hospitalization data until 3.0 ± 0.25 years. Activities of daily living, battery of physical performance tests, Mini-Mental State Examination, and 15-item Geriatric Depression Scale at baseline and after 1.7 ± 0.2 years.

Results: Individuals in the lowest quartile of FEV₁ expressions had higher adjusted risk than the rest of study population for all-cause mortality (highest hazard ratio 2.05 [95% Confidence Interval 1.50-2.80] for FEV₁Q and 2.01 [1.47-2.76] for FEV₁/Ht³), first hospitalization (highest hazard ratio 1.63 [1.21-2.16] for FEV₁/Ht² and 1.61[1.20-2.16] for FEV₁/Ht³), mental decline (highest odds ratio 2.80 [1.61-4.89] for FEV₁Q) and physical decline (only FEV₁/Ht³ with odds ratio 1.93 [1.13-3.30]). Based on risk classification improvement measures, FEV₁/Ht³ and FEV₁Q performed better than FEV₁PP.

Conclusion: In a cohort of adults aged 80 and older, FEV₁ expressions that are independent of reference values (FEV₁/Ht³ and FEV₁Q) were better at predicting adverse health outcomes than traditional expressions that depend on reference values, and should be used in further research on FEV₁ and aging.

Keywords: FEV1 expressions; adults aged 80 and older; adverse health outcomes.