Study of Pulmonary Function Tests in Type 2 Diabetes Mellitus and Their Correlation with Glycemic Control and Systemic Inflammation

Introduction: Reduced lung function in diabetes has been described for long but its clinical importance is not yet clear. Also, limited literature is available regarding its association with sugar control, and its correlation with inflammatory markers. Thus, we aimed to study the pulmonary function test abnormalities and systemic inflammation in type 2 diabetes mellitus. Material and methods: 100 patients with type 2 diabetes were divided into two groups depending on control of diabetes (group A–HbA1C ≤ 7% and group B-HbA1C > 7%). All the subjects selected underwent detailed evaluation including testing for HbA1C, HsCRP (high-sensitivity C-reactive protein), serum ferritin and serum fibrinogen, along with pulmonary function testing. Results: Percentage predicted FVC (forced vital capacity), FEV1 (forced expiratory volume in 1 second) and SVC (slow vital capacity) were significantly reduced, while mean values of inflammatory markers [fibrinogen (p < 0.001) and hsCRP (p < 0.002)] were significantly higher in uncontrolled diabetes group. There was a significant negative correlation between FEV1 (r = –0.739, p < 0.001), FVC (r = –0.370, p < 0.001), SVC (r = –0.635, p < 0.001) with HbA1C. HbA1C had a positive correlation with hsCRP (r = –0.308, p < 0.002) and fibrinogen (r = 0.388, p < 0.001). Conclusion: Pulmonary functions were decreased and inflammatory markers like hsCRP, fibrinogen, and ferritin significantly increased in uncontrolled diabetics. Also, a potential association was seen between higher values of inflammatory markers like hsCRP and fibrinogen and decrease in lung function. This information, requiring confirmation with larger multicentre studies, remains important because of potential epidemiological, clinical and therapeutic implications.