Applicability of the Old European Respiratory Society/European Community for Steel and Coal reference equations for spirometry interpretation in Tunisian adult population.

BACKGROUND: Tunisian pulmonary functional laboratories accept the default settings for reference equations (European Respiratory Society/European Community for Steel and Coal (ERS/ECSC1983) offered by the manufacturer even though adult Tunisian reference equations (Tunisian1995) are available. OBJECTIVE: To compare the spirometric profile of Tunisian subjects, according to the two reference equations. POPULATION AND METHODS: Spirometric data were recorded from 1192 consecutive spirometry procedures in adults aged 18-60 years. Reference values and lower limits of normality (LLN) were calculated using the two reference equations. Applied definitions: large airway obstructive ventilatory defect (LAOVD): ratio between the 1st second expiratory volume and forced vital capacity (FEV1/FVC) < LLN. Small AOVD (SAOVD): FEV1/FVC > LLN and FVC > LLN and maximal midexpiratory flow < LLN. Tendency through a restrictive ventilatory defect (TRVD): FEV1 and FVC < LLN. The spirometric profile, according the two reference equations, was determined. RESULTS: Using Tunisian1995 reference equations, 34%, 7%, 37% and 19% of spirometry records were interpreted as normal, and as having, LAOVD, SAOVD and TRVD, respectively. Using ERS/ECSC1983 reference equations, 85%, 3%, 9% and 2% of spirometry records were interpreted as normal, and as having, LAOVD, SAOVD and TRVD, respectively. Using the ERS/ECSC1983 reference equations, misclassification was worse for LAOVD, for SAOVD and for TRVD, respectively, 68%, 94% and 89%. CONCLUSION: Our results showed that the use of the old Caucasian reference equations resulted in misinterpretation of spirometry data in a significant proportion of subjects. This could result in inappropriate diagnosis and/or management.

The recent multi-ethnic global lung initiative 2012 (GLI2012) reference values don't reflect contemporary adult's North African spirometry.

BACKGROUND: The applicability of the recent multi-ethnic reference equations derived by the ERS Global Lung Initiative (ERS/GLI) in interpreting spirometry data in North African adult subjects has not been studied. OBJECTIVE: To ascertain how well the recent ERS/GLI reference equations fit contemporary adult Tunisian spirometric data. POPULATION AND METHODS: Spirometric data were recorded from 1192 consecutive spirometry procedures in adults aged 18-60 years. Reference values and lower limits of normality (LLN) were calculated using the local and the ERS/GLI reference equations. Applied definitions: large airway obstructive ventilatory defect (LAOVD): FEV1/FVC < LLN. Tendency to a restrictive ventilatory defect (TRVD): FEV1 and FVC < LLN and FEV1/FVC ≥ LLN. The spirometric profile, according to the two reference equations, was determined. Z-scores for spirometry from North African healthy subjects (n = 489) were calculated. If the average Z-score deviated by <± 0.5 from the overall mean, the ERS/GLI reference equations would be considered as reflective of contemporary Tunisian spirometry. RESULTS: Using Tunisian reference equations, 71.31%, 6.71% and 19.04% of spirometry records were interpreted as normal, and as having, LAOVD and TRVD, respectively. Using the ERS/GLI reference equations, these figures were respectively, 85.82%, 4.19% and 8.39%. The mean ± SD Z-scores for the contemporary healthy North African subject's data were -0.55 ± 0.87 for FEV1, -0.62 ± 0.86 for FVC and 0.10 ± 0.73 for FEV1/FVC. CONCLUSION: The present study don't recommend the use of the recent ERS/GLI reference equations to interpret spirometry in North African adult population.