Role of Duration of Diabetes on Ventilatory Capacities and Expiratory Flow Rates in Type 2 Diabetes Mellitus

Abstract

Diabetes mellitus is a chronic debilitating problem with increasing incidence and long term complications such as diabetic nephropathy, diabetic neuropathy, diabetic retinopathy etc. These complications are mainly a consequence of macro vascular and micro vascular damages of the target organs. The magnitude of the complications of diabetes is related to its duration. Less has been known about the after effects of diabetes on lungs. So this work was carried out to know the relation between duration of diabetes and lung volumes and capacities in Type 2 DM patients. The presence of an extensive micro vascular circulation and abundant connective tissue in the lungs raises the possibility that lung tissue may be affected by Microangiopathy process and non-enzymatic glycosylation of tissue proteins, induced by chronic hyperglycemia, there by rendering the lung a “target organ” in diabetic patients.  This is a cross-sectional study, the test group were Type 2 Diabetes Mellitus patients (n=50) with duration of 2-35 years, the control group were staff of Narayana medical college (n=50). Written consent was obtained from them. The following lung function parameters were recorded: Forced Vital Capacity (FVC), Forced Expiratory Volume in the first second (FEV₁), Forced Expiratory Volume percent (FEV₁/FVC %), Peak Expiratory Flow Rate (PEFR), Forced Expiratory Flow 25-75% (FEF_25-75%), Maximum Voluntary Ventilation (MVV). The mean FVC, FEV₁, PEFR, FEF_25-75%, MVV values are low in diabetics compared to controls (p value <0.001) and the parameters showed significant negative correlation with duration of diabetes.

Key words: Chronic hyperglycemia, Diabetes mellitus, Microangiopathy, Micro vascular circulation, Pulmonary function tests