Connecting sugar and fibrosis: Diabetes as a hidden player in rheumatoid arthritis-associated interstitial lung disease

Abstract

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease that extends beyond joint inflammation, affecting pulmonary and metabolic pathways. Interstitial lung disease (ILD) is one of its most serious extra-articular complications, while type 2 diabetes mellitus (T2DM) frequently coexists with RA and may exacerbate inflammatory and fibrotic processes. This editorial discusses the study by Sutton et al, the largest population-based analysis to date exploring the link between T2DM and ILD in patients with RA, and reflects on its mechanistic and clinical implications. In a nationwide cohort of more than 120000 hospitalized RA patients, Sutton et al demonstrated that the coexistence of T2DM nearly doubles the odds of developing ILD (odds ratio = 2.02; 95% confidence interval: 1.84-2.22), with additional increases in pulmonary hypertension, pneumothorax, and length of stay. These findings reinforce the concept of a metabolic-pulmonary-autoimmune axis, in which chronic inflammation promotes insulin resistance and metabolic dysfunction, while hyperglycaemia and advanced glycation end-products amplify oxidative stress and fibrogenesis. This reciprocal interaction may induce a self-perpetuating cycle of “metaflammation”, fibrosis, and organ damage. Conclusion: Recognizing diabetes as a silent amplifier of RA-associated ILD redefines the interface between rheumatology, pulmonology, and endocrinology. Early detection and integrated management of metabolic and pulmonary comorbidities should be prioritized, while future studies must determine whether optimizing glycemic control can attenuate pulmonary fibrosis and improve long-term outcomes.

Keywords: Fibrosis; Metaflammation; Pathophysiology; Interstitial lung disease; Rheumatoid arthritis; Type 2 diabetes mellitus

Core Tip: Rheumatoid arthritis is a systemic autoimmune disease with significant extra-articular morbidity, including interstitial lung disease. Emerging evidence identifies type 2 diabetes mellitus as a significant, yet poorly recognized, modifier of pulmonary risk in rheumatoid arthritis. In this editorial, we discuss, together with the article by Sutton et al, the mechanistic, epidemiological, and clinical data that support a metabolic-pulmonary-autoimmune axis.