Lung function data of North-African patients with rheumatoid arthritis: acomparative study between anti-citrullinated peptides antibodies positive and negative patients

Introduction. Although lung damages are among the leading causes of death from Rheumatoid Arthritis (RA), few studies have assessed the spirometric and plethysmographic data and profile of patients with RA, particularly those with Anti-Citrullinated Peptides Antibodies Positive (ACPA+). Aim. To compare the spirometric and plethysmographic data and profile of RA patients ACPA+ and ACPA-. Methods. This comparative pilot study was performed over a two-year period (2018-2019) in Algiers (Algeria). The study included two groups of RA non-smoker patients: 26 ACPA+ and 33 ACPA-. RA was diagnosed according to the ACR/EULAR 2010 RA classification criteria. Spirometry and plethysmography were performed. The following definitions were applied: Obstructive Ventilatory Impairment (OVI): FEV1/FVC z-score < -1.645; Restrictive Ventilatory Impairment (RVI): Total Lung Capacity (TLC) z-score < -1.645; Mixed Ventilatory Impairment (MVI): FEV1/FVC z-score < -1.645 and TLC z-score < -1.645; lung- hyperinflation: residual volume z-score > +1.645; Nonspecific Ventilatory Impairment (NSVI): FEV1 z-score < -1.645, FVC z-score < -1.645, FEV1/FVC z-score ≥ -1.645, and TLC z-score ≥ -1.645. Results. The ACPA- group was older than the ACPA+ one by ∼ 10 years (63±13 vs. 53±12 years, p=0.0025; respectively). The ACPA+ and ACPA- groups included comparative percentages of patients having RVI, MVI, and NSVI (23.1 vs. 45.5%, p=0.0745; 3.8 vs. 3.0%, p=0.8654; and 7.7 vs. 6.1%, p=0.8086; respectively). Compared to the ACPA- group, the ACPA+ group included a higher percentage of patients having OVI and lung-hyperinflation (9.1 vs. 38.5%, p=0.0069; 9.1 vs. 42.3%, p=0.0029; respectively). Conclusion. Compared to the ACPA- group, the ACPA+ one had more lung-hyperinflation and OVI, and comparative percentages of RVI, MVI, and NSVI.