A Cross-Sectional Study of Pulmonary Function Tests in Type 2 Diabetes Mellitus and Correlation with Glycemic Index and Duration of Diabetes

BACKGROUND Diabetes mellitus is a metabolic disorder of multiple etiologies characterized by chronic hyperglycemia and complicated by involvement of many organs like cardiovascular system, nervous system, renal system and respiratory system. AIMS AND OBJECTIVES The study was undertaken to study various pulmonary function parameters in type 2 diabetic patients and compare them with matched healthy subjects and study its association with the duration of diabetes and glycosylated hemoglobin (HBA1c). MATERIALS AND METHODS Pulmonary function tests (PFTs) were recorded in type 2 diabetic patients and normal healthy controls, 72 males in each group, aged 35-55 years using Medspiror (computerized spirometer). PFT parameters, which were recorded were - FVC, FEV1, FEV1%, MMEFR 25-75%, MMEFR 0.2-1.2 L, PEFR, FEV3 and MVV. PFTs of diabetic patients and controls were compared by applying student's unpaired t test. Association of PFTs with HbA1c and duration of illness in diabetic patients was analyzed by applying Pearson's correlation coefficient. RESULTS There was a significant decrease in FVC, FEV1 and FEV1% in type 2 diabetic patients when compared with the healthy controls, whereas the other PFT parameters, MMEFR 25-75%, MMEFR 0.2-1.2L, PEFR and MVV did not show significant changes when compared to the control group. The impairment in pulmonary function was found to be more marked with the duration of diabetes and increased levels of glycosylated hemoglobin. CONCLUSION The present study is suggestive of impairment in pulmonary functions (restrictive type). Also all the lung function parameters, except MMEFR 0.2-1.2 L had a positive correlation with the duration of diabetes and HbA1c (glycosylated hemoglobin).