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The distribution of peak expiratory flow variability in a population sample
B G Higgins1, J R Britton, S Chinn
1Respiratory Medicine Unit, City Hospital, Nottingham, UK.
The American Review of Respiratory Disease
|November 1, 1989
Summary
Peak expiratory flow (PEF) variability assessment is crucial for airflow obstruction. Amplitude percent mean and standard deviation percent mean are recommended for epidemiological studies, with amplitude percent mean being the preferred index.
Area of Science:
- Pulmonary Medicine
- Epidemiology
- Respiratory Physiology
Background:
- Serial peak expiratory flow (PEF) measurements are commonly used to evaluate airflow obstruction variability.
- However, population-based PEF variability ranges and standardized expression methods are lacking.
Purpose of the Study:
- To define the expected range of PEF variability in the general population.
- To identify the most suitable index for expressing PEF variability in epidemiological research.
Main Methods:
- Compared PEF recordings from 121 randomly selected individuals and 221 with recent wheeze.
- Subjects recorded PEF every 2 hours for 7 days using a mini-Wright peak flow meter.
- Derived and analyzed seven indices of PEF variability.
Main Results:
- All PEF variability indices exhibited a positively skewed distribution in the general population sample.
- Standard deviation percent mean and amplitude percent mean showed the best discrimination between asthmatic/wheezing subjects and others.
- These two indices also demonstrated the highest intra-class correlation coefficients.
Conclusions:
- Amplitude percent mean and standard deviation percent mean are the most effective indices for expressing PEF variability in epidemiological studies.
- Amplitude percent mean is simpler to calculate and is the recommended index of choice.
- PEF variability is continuous in the general population, without a clear distinction between asthmatic and non-asthmatic individuals.