Association Between Duration of Type 2 Diabetes Mellitus and Decline in Pulmonary Function: A Cross-sectional Observational Study

Abstract

Background: Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder characterized by persistent hyperglycaemia resulting from insulin resistance and progressive β-cell dysfunction. Although the classical complications of diabetes involve the retina, kidneys, nerves, and cardiovascular system, increasing evidence suggests that the lungs may also represent an important target organ affected by chronic hyperglycaemia. The extensive pulmonary microvascular network and connective tissue matrix are susceptible to non-enzymatic glycation, oxidative stress, and microangiopathic changes associated with long-standing diabetes. These pathological alterations may result in progressive deterioration of pulmonary function. The present study was conducted to evaluate the association between duration of T2DM and decline in pulmonary function among diabetic patients attending a tertiary care centre.
Methods: A hospital-based cross-sectional observational study was conducted among 171 patients with T2DM attending the Department of Medicine, Government Bundelkhand Medical College and Hospital, Sagar, Madhya Pradesh, over a period of 18 months. Demographic, anthropometric, clinical, and biochemical parameters were recorded. Pulmonary function tests (PFTs) were performed using computerized spirometry. The association between duration of diabetes and pulmonary dysfunction was analysed using appropriate statistical methods. A p-value <0.05 was considered statistically significant.
Results: Among the 171 participants, 57.9% had diabetes duration greater than five years. Pulmonary dysfunction was observed in 60.8% of participants, with a restrictive pattern being the most common abnormality (43.3%). Patients with diabetes duration greater than five years showed significantly higher prevalence of abnormal pulmonary function tests compared with those having diabetes duration ≤5 years (74.0% vs. 43.1%; p=0.002). Multivariate logistic regression demonstrated that longer duration of diabetes independently predicted pulmonary dysfunction (Adjusted OR=2.48; 95% CI: 1.32–4.67; p=0.005).
Conclusion: Longer duration of T2DM is significantly associated with decline in pulmonary function. Routine pulmonary function assessment may facilitate early detection of respiratory impairment in patients with longstanding diabetes mellitus.