A Study of Peak Expiratory Flow Rate in Patients with Type 2 Diabetes Mellitus

Background: The peak expiratory flow rate (PEFR) is the maximal airflow during a forced expiratory vital capacity manoeuvre starting from a position of full inspiration. In healthy subjects this index reflects the calibre of the central airways and the force exerted by the expiratory muscles. Lungs are a potential target organ for diabetic microvascular complications. This is due to non-enzymatic glycosylation of proteins particularly collagen and elastin, as well as microangiopathy induced by chronic hyperglycemia. The thickening of the pulmonary capillary basal lamina and the alveolar epithelium and reduction in elastic recoil of the lung may result in decrease in the expiratory volume of air. Aims and Objectives: The study was undertaken to analyze the PEFR in type II diabetic patients and compare them with age and gender matched healthy control. Correlation between PEFR in diabetic patients with glycemic status and duration of the disease was also analyzed. Materials and Methods: A cross-sectional study was conducted among 100 type 2 diabetic patients and 100 normal healthy controls aged between 30 - 60 years to record PEFR by spirometer and to find the correlation between mean PEFR in diabetics and non - diabetics. Glycemic status – Fasting blood sugar (FBS) and Postprandial blood sugar (PPBS) of subjects were determined by glucose oxidase and peroxidase methods. PEFR of diabetic patients and controls were compared by applying Student’s unpaired t test. Associations between PEFR and duration of illness in diabetic patients were analyzed by applying Pearson’s coefficient. Results: The mean PEFR in the total diabetic group is 265.35 ± 114.46 L/min which is lower than that of the total non-diabetic control group (359.71±123.68 L/min ) and the decreased value in the total diabetic control group is very highly significant (p<0.001). There is no significant correlation between PEFR with FBS among the total diabetic group (r = - 0.1, p > 0.05). There is no significant correlation of PEFR and PPBS among the diabetic cases (r = 0.04, p> 0.05) in this study. No significant correlation is observed between PEFR with the duration of disease among the total diabetic group (r = 0.00, p > 0.05). Conclusion: Our study concluded that impairment of pulmonary function (PEFR) is associated with diabetes mellitus.