A Study of Effect of Glycaemic Status on Pulmonary Function Test in Type 2 Diabetes Mellitus

BACKGROUND Diabetes mellitus is a metabolic disorder precipitating micro vascular, macro vascular complications and peripheral vascular diseases. Pulmonary complications of diabetes mellitus have been poorly characterised. Glycaemic status has shown varied impact on lung functions. In type-2 diabetes there is resistance to insulin action and also inadequate insulin secretion. Diabetes mellitus is associated with morphological and functional abnormalities. Several studies have shown that diabetes is associated with impaired pulmonary function. Pulmonary complications of diabetes mellitus (DM) have been poorly characterised. Some authors have reported normal pulmonary functions and even concluded that spirometry is not at all necessary in diabetic patients. We wanted to highlight the evidence-based significance of spirometry. METHODS This cross-sectional study was done for a period of 1 year from September 2017 to July 2018. The study sample consisted of 50 type-2 diabetes patients and 50 controls. RESULTS A total of 100 subjects were included in the present study; 50 of them were diabetics and the other 50 were non-diabetic controls matched by age, sex and body mass index (BMI). The range of forced vital capacity (FVC) in diabetic group was from 1.36 litres, which is lesser than range in controls (2.06 litres). Forced expiratory volume (FEV1) / FVC ranged from 0.59 in diabetics compared to 0.84 in controls. Mean FVC value was higher in diabetics with a duration of diabetes of less than 5 years (2.72) as compared to those with diabetes of more than 5 years (2.03) with a P value of 0.0004 which is statistically significant. CONCLUSIONS Type 2 diabetes mellitus is associated with restrictive pattern of respiratory abnormality. As the duration of diabetes increases the restrictive profile was more prominent. There was inverse relation between glycaemic status and spirometric indices FEV1 and FVC. Thus, an intensive glycaemic management may reduce the risk of death through an improved ventilator function which is independent of the other beneficial effects. KEY WORDS Pulmonary Function Test, Type 2 Diabetes Mellitus, Glycaemic Status