Diagnostic outcomes of the 2023 race-neutral and 2012 race-specific global lung function initiative spirometry equations in healthy Algerian adults: a cross-sectional comparative analysis.

In 2023, the Global Lung Function Initiative (GLI) introduced race-neutral spirometric reference equations (2023-GLI-RNEs) to address concerns of racial bias inherent in earlier 2012-GLI race-specific models. While the 2012-GLI Caucasian equations (2012-GLI-CEs) were previously identified to reflect contemporary adults' Algerian spirometry, the 2023-GLI-RNEs applicability remains untested. This study aimed to compare the diagnostic outcomes of the 2023-GLI-RNEs and the 2012-GLI-CEs in a healthy adult Algerian population. A cross-sectional study was conducted on 488 Algerian healthy adults (49.6% female) aged 18-85 years. Participants underwent standardized plethysmography/spirometry in accordance with the most updated international guidelines. Z-scores and percent predicted values for FEV₁, FVC, and FEV₁/FVC ratio were computed using both 2012-GLI-CEs and 2023-GLI-RNEs. Diagnostic classifications (e.g. normal pattern, obstructive ventilatory impairment (OVI), non-specific ventilatory impairment (NSVI), or spirometric restrictive pattern (SRP), isolated low FEV1 (ILF)) were compared across the two equations. Classification changes between the two norms appeared to be relatively limited. Percent predicted FEV₁ and FVC values were significantly but slightly higher when interpreted using 2023-GLI-RNEs by 6% and 7% points, respectively, and the percent predicted FEV₁/FVC value was marginally lower by -0.9%. Compared to 2012-GLI-CEs, 2023-GLI-RNEs identified more cases of OVI (4.10% vs. 6.35%, respectively, p = 0.003), fewer cases of NSVI or SRP (2.05% vs. 0.20%, respectively, p = 0.008) or ILF (1.84 vs. 0.00%, respectively, p = 0.008), and comparable cases of normal spirometry (92.01% vs. 93.44%, respectively, p = 0.230). In a sample of healthy Algerian adults' spirometric data, 2023-GLI-RNEs and 2012-GLI-CEs produced broadly comparable classifications of normal spirometry, although modest but statistically significant differences were observed in several abnormal spirometric categories.