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[Common prediction equations of respiratory function tests from children to adults in Japan]
Gen Tamura1, Hisamichi Aizawa, Atsushi Nagai
1First Department of Internal Medicine, Kurume University School of Medicine.
Insights
This study developed common prediction equations for respiratory function tests (RFTs) in Japan, applicable from children to adults. The new equations, based on age and height, offer high efficiency for various RFT measurements.
Area of Science:
- Pulmonary Physiology
- Biostatistics
Context:
- Establishing accurate reference values for respiratory function tests (RFTs) is crucial for diagnosing and monitoring lung diseases.
- Previous RFT reference values in Japan were limited by age groups or specific regions.
Purpose:
- To develop unified, sex-specific prediction equations for key RFTs applicable across a wide age range in the Japanese population.
- To combine existing RFT datasets to create more robust predictive models.
Summary:
- Data from two Japanese RFT studies (2001 and 2006) were merged. Multiple regression analysis was performed on forced vital capacity, forced expiratory volume in 1 second (FEV1), V50, V25, and Gaensler's FEV1%. Equations incorporating age, height, age squared, and age x height demonstrated high efficiency.
- The final common prediction equations excluded height squared, proving effective for all analyzed RFTs.
Impact:
- Provides a standardized method for predicting normal RFT values in Japanese individuals from childhood to adulthood.
- Facilitates more consistent interpretation of spirometry results across different clinical settings and age groups in Japan.
- Aims to improve the accuracy of diagnosing respiratory conditions by offering reliable reference ranges.
Abstract:
In order to make common prediction equations of respiratory function tests (RFTs) from children to adults in Japan, we combined data of RFTs accumulated for "Reference values of spirogram and arterial blood gas levels in Japanese" reported in 2001 at the Japanese Respiratory Society congress and those for "An attempt to establish reference vales of respiratory function tests for Japanese children and adolescents" reported in 2006 from the Tohoku district. We then conducted multiple regression analysis on forced vital capacity, forced expiratory volume in 1 second (FEV1), V50, V25, and Gaensler's FEV1%, since they were measured under the same condition in the both reports. With all the combinations of 5 dependent variables (age, height, age2, height2, and age x height), multiple regression analysis was performed for each RFT. Judging by both evaluation indices of adjusted R-square and Mallows's Cp statistic, the equation using 4 dependent variables of age, height, age2, and age x height demonstrated roughly high efficiency for all RFTs. Therefore, we decided the equation excluding a dependent variable of height2 as common prediction equations for all RFTs and demonstrated the prediction equation for each RFT by sex.
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