Differences in functional impairment diagnosis using global lung initiative (GLI) predictive values for spirometry

Aim To assess the differences in functional impairment diagnosis in Romanian subjects with various lung diseases using two sets of predictive values for spirometry: ERS93 (obtained from a 25-70 years old West-European population) and the new GLI equations. Methods Spirometry sessions performed using ATS/ERS quality criteria were evaluated. Predicted values, lower limit of normal and %predicted for FVC, FEV1, FEV1/FVC, FEF25-75 and MEF25 were compared using GLI and ERS93 equations in subjects with various ages, gender or heights. Functional impairment was assessed using ATS/ERS recommendations. Results Spirometry was evaluated in 124 consecutive subjects aged 18-82 years, height 1.50-1.93m, 54 males. Using GLI set, FVC and FEV1 %predicted were lower than using ERS93 set ( mean difference in percent-points -8±4 for FVC, -4±3 for FEV1), while FEF25-75 and MEF25 %predicted values were higher ( mean difference 10±9 for FEF25-75, 39±32 for MEF25). Differences were significantly larger in older (>70yo), shorter (<1.55m), and female subjects (p<0.05). Normal spirometry was seen in 53 subjects using GLI and in 64 using ERS93 (in 52 concordantly); impairment severity was concordant in 49 subjects. Restriction was diagnosed in 28 subjects (23%) using GLI and in only 14 (11%) using ERS93, while obstruction in 56 (45%) and 52 (42%) respectively. Conclusion In this Romanian population we found significant differences in spirometric values using GLI versus ERS93, larger for women, shorter and older subjects. Functional diagnosis was non-concordant in 23 subjects (18%), with more spirometric restrictions and obstructions diagnosed using GLI equations and more severe impairments.