Incidence of airflow limitation in subjects 65–100 years of age

Abstract

The true incidence of chronic obstructive pulmonary disease is largely unknown, because the few longitudinal studies performed have used diagnostic criteria no longer recommended by either the European Respiratory Society or the American Thoracic Society (ATS).We studied the incidence and significance of airflow limitation in a population-based geriatric sample using both an age-dependent predicted lower limit of normal (LLN) value and a fixed-ratio spirometric criterion.Out of 2025 subjects with acceptable spirometry at baseline, 984 subjects aged 65–100 years completed a 6-year follow-up visit. Smoking habits were registered at baseline. Exclusion criteria were non-acceptable spirometry performance according to ATS criteria and inability to communicate. Airflow limitation was defined both according to forced expiratory volume in 1 s (FEV1)/forced vital capacity ratio <0.7 and <LLN.The incidence of airflow limitation per 1000 person-years was 28.2 using a fixed ratio and 11.7 with LLN, corresponding to a 1.41-fold higher incidence rate using a fixed ratio. The incidence increased dramatically with age when using a fixed ratio, but less so when using LLN. In addition, a sex effect was observed with the LLN criterion. LLN airflow limitation was associated with increased 5-year mortality. Presence of fixed-ratio airflow limitation in individuals classified by LLN as non-obstructive was not associated with increased mortality.

Ageing lungs and very elderly COPD: anytime and anywhere

“…)", as well as those studies that compare outcomes among individuals diagnosed with chronic obstructive pulmonary disease (COPD) on the basis of the fixed ratio versus lower limit of normal (LLN) thresholds. In this issue of the European Respiratory Journal (ERJ), LUOTO et al [2] report the results of a study that fulfils both goals.…”

“…As reviewed by LUOTO et al [2], there were few studies quantifying the incidence of spirometrically confirmed COPD in the literature, particularly within the elderly. As exemplified in their table 5, there is a wide heterogeneity in the published estimates of incidence, varying by method, location, age and sex.…”

“…LUOTO et al [2] followed for 6 years nearly a thousand individuals aged 65-100 years who had an acceptable spirometry at baseline. They participated in the longitudinal Good Aging in Skåne study, which in turn is part of the Swedish National Study on Aging and Care.…”

“…However, given the likely ecological fallacy [5], for a universally very high level of underdiagnosis [6], there are many questions that remain unanswered relating to the elderly with COPD. A research call for COPD in the elderly, similar to that for asthma in the elderly, is needed [7].As reviewed by LUOTO et al [2], there were few studies quantifying the incidence of spirometrically confirmed COPD in the literature, particularly within the elderly. As exemplified in their table 5, there is a wide heterogeneity in the published estimates of incidence, varying by method, location, age and sex.…”

Assessment of severity and prognosis in COPD: moving beyond percent of predicted

“…There is also abundant evidence that this reduction is most accurately identified as an individual value less than the lower limit of the normal range (LLN) specific to that individual, as determined from an appropriate healthy, non-smoking, reference population [1]. Because the FEV1/FVC ratio declines normally with age, using a non-individualised cut-off, such as 0.70, has been shown to cause an unacceptable level of misclassification with age and sex bias; this leads to over-diagnosis of 30% or more of older men and under-diagnosis of younger women [2][3][4][5]. There is much less consensus, however, on methods to indicate disease severity or to assess the likelihood of future outcomes.…”