[New spirometric reference equations for healthy Chilean adults]

To correctly interpret spirometric results, reference values should come from the same population. Current spirometric reference equations have been under scrutiny due to deficiencies to fit adequately for Chilean population, specially, for those aged over 65 years old.

To develop new spirometric reference values for Chilean adults, based on national studies in which spirometries were performed in healthy non-smoker adults.

A standardized database of spirometric values was developed combining spirometric data collected from five population-based studies, in which healthy nonsmoker adults participated. Spirometries from 448 males aged 19 to 84 years and from 726 females aged 19 to 94 years, obtained according to guidelines from the American Thoracic and European Respiratory Societies, were analyzed. Using multiple regression models, which included height, gender, and age, the theoretical value and inferior limits of normality were calculated for 1st second (FEV1), forced vital capacity (FVC), FEV1/FVC, and forced mid-expiratory flow rate (FEF25-75).

Reference values and lower limits of normality (LLN) were constructed for Chilean adults of both genders. The new proposed set of equations had a better fit, when compared with the current reference values used in Chile.

The new spirometric references values derived from this study, fit better than currently used ones. Therefore, they should be used as new references values for Chilean adults.