Prevalence of abnormal findings when adopting new national and international Global Lung Function Initiative reference values for spirometry in the Finnish general population

Peer reviewe

Spirometrian suorittaminen ja tulkinta : uudet suomalaiset ja monikansalliset viitearvot käyttöön - Suomen Kliinisen Fysiologian yhdistyksen ja Suomen Keuhkolääkäriyhdistyksen suositus 2015

•Hil­jattain on jul­kaistu uu­det suoma­laiset ai­kuisten spi­ro­metrian vii­tearvot, joi­den mit­taukset kat­tavat myös vanhus­väestön 84 vuo­den ikään as­ti. •Uu­sien ar­vojen tulkin­nassa otetaan käyt­töön mi­tatun ar­von poik­keaman mää­rä viitear­vo­po­pu­laation ­kes­kiar­vosta z-yksik­köinä (sama kuin SD). Muu­toksen vaikeu­saste ar­vioidaan z-ar­von mu­kaan. •Nor­maalin va­riaation ala­raja on klii­ni­sissä tutki­muk­sissa kai­kille spi­ro­met­ria­muut­tu­jille sa­ma (z-ar­vona –1,65). Ter­veistä 95 % asettuu tä­män ra­jan ylä­puo­lelle. •Syn­ty­pe­rältään ulko­maa­laisten las­ten ja ai­kuisten tutki­muk­sissa suosi­tellaan käytet­tä­väksi uu­sia kansain­vä­lisiä GLI2012-vii­tear­voja. •Suo­ma­laisten las­ten tutki­muk­sissa suosi­tellaan käytet­tä­väksi edelleen van­hoja suoma­laisia viitear­voja, mut­ta nii­den klii­ni­sessä sovel­ta­mi­sessa suosi­tellaan nyt z-ar­vojen käyt­töä. •Ai­kuisten van­hat suoma­laiset vii­tearvot ei­vät ole perus­tuneet todel­lisiin mittaus­tu­loksiin yli 64-vuo­tiailla. Van­hojen ar­vojen käyt­tö on aiheut­tanut toden­nä­köi­sesti hengi­tys­tieobst­ruktion yli­diag­nos­tiikkaa vanhem­missa ikä­ryh­missä.Peer reviewe

Evaluation of the global lung function initiative 2012 reference values for spirometry in a Swedish population sample

Background: The Global Lung Function Initiative 2012 (GLI) reference values are currently endorsed by several respiratory societies but evaluations of applicability for adults resident in European countries are lacking. The aim of this study was to evaluate if the GLI reference values are appropriate for an adult Caucasian Swedish population. Methods: During 2008-2013, clinical examinations including spirometry were performed on general population samples in northern Sweden, in which 501 healthy Caucasian non-smokers were identified. Predicted GLI reference values and Z-scores were calculated for each healthy non-smoking subject and the distributions and mean values for FEV1, FVC and the FEV1/FVC ratio were examined. The prevalence of airway obstruction among these healthy non-smokers was calculated based on the Lower Limit of normal (LLN) criterion (lower fifth percentile) for the FEV1/FVC ratio. Thus, by definition, a prevalence of 5% was expected. Results: The Z-scores for FEV1, FVC and FEV1/FVC were reasonably, although not perfectly, normally distributed, but not centred on zero. Both predicted FEV1 and, in particular, FVC were lower compared to the observed values in the sample. The deviations were greater among women compared to men. The prevalence of airway obstruction based on the LLN criterion for the FEV1/FVC ratio was 9.4% among women and 2.7% among men. Conclusions: The use of the GLI reference values may produce biased prevalence estimates of airway obstruction in Sweden, especially among women. These results demonstrate the importance of validating the GLI reference values in different countries.Peer reviewe

Converting FENO by different flows to standard flow FENO

In clinical practice, assessment of expiratory nitric oxide (F-ENO) may reveal eosinophilic airway inflammation in asthmatic and other pulmonary diseases. Currently, measuring of F-ENO is standardized to exhaled flow level of 50 ml s(-1), since the expiratory flow rate affects the F-ENO results. To enable the comparison of F-ENO measured with different expiratory flows, we firstly aimed to establish a conversion model to estimate F-ENO at the standard flow level, and secondly, validate it in five external populations. F-ENO measurements were obtained from 30 volunteers (mixed adult population) at the following multiple expiratory flow rates: 50, 30, 100 and 300 ml s(-1), after different mouthwash settings, and a conversion model was developed. We tested the conversion model in five populations: healthy adults, healthy children, and patients with COPD, asthma and alveolitis. F-ENO conversions in the mixed adult population, in healthy adults and in children, showed the lowest deviation between estimated FENO from 100 ml s(-1) and measured F-ENO at 50 mL s(-1): -0 center dot 28 ppb, -0 center dot 44 ppb and 0 center dot 27 ppb, respectively. In patients with COPD, asthma and alveolitis, the deviation was -1 center dot 16 ppb, -1 center dot 68 ppb and 1 center dot 47 ppb, respectively. We proposed a valid model to convert F-ENO in healthy or mixed populations, as well as in subjects with obstructive pulmonary diseases and found it suitable for converting F-ENO measured with different expiratory flows to the standard flow in large epidemiological data, but not on individual level. In conclusion, a model to convert F-ENO from different flows to the standard flow was established and validated.Peer reviewe