Predicting future risk of asthma exacerbations using individual conditional probabilities.
J Allergy Clin Immunol
; 127(6): 1494-502.e3, 2011 Jun.
Article
em En
| MEDLINE
| ID: mdl-21333347
ABSTRACT
BACKGROUND:
Determination of future risk of exacerbations is a key issue in the management of asthma. We previously developed a method to calculate conditional probabilities (π) of future decreases in lung function by using the daily fluctuations in peak expiratory flow (PEF).OBJECTIVE:
We aimed to extend calculation of π values to individual patients, validated by using electronically recorded data from 2 past clinical trials.METHODS:
Twice-daily PEF data were analyzed from 78 patients with severe (study A) and 61 patients with poorly controlled (study B) asthma. For each patient, the π value was calculated from 5000 PEF data points simulated based on the correlation and distribution properties of observed PEF. Given an initial PEF, the π value was defined as the probability of a decrease in PEF to less than 80% of predicted value on 2 consecutive days within a month. These probabilities were then compared with actual occurrences of such events and clinically defined exacerbations within the following month.RESULTS:
π Values were related to actual occurrences of decreases in PEF (adjusted R(2) > 0.800 for both studies). Every increase of 10% in π value was associated with an odds ratio of having a future exacerbation of 1.24 (95% CI, 1.07-1.43) for study A and 1.13 (95% CI, 1.02-1.26) for study B, with better sensitivity and specificity than clinic-measured FEV(1).CONCLUSION:
These results from 2 independent datasets with differing asthmatic populations and differing exacerbation criteria provide support that clinically relevant quantification of individual future risk of exacerbations is possible.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Asma
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Pico do Fluxo Expiratório
Tipo de estudo:
Etiology_studies
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Observational_studies
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Prognostic_studies
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Risk_factors_studies
Limite:
Adolescent
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Adult
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Aged
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Female
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Humans
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Male
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Middle aged
Idioma:
En
Ano de publicação:
2011
Tipo de documento:
Article