A Step Toward the Exploration of Better Spirometric Parameters for Early Diagnosis of Pulmonary Dysfunction in Persons With Type 2 Diabetes Mellitus

Objectives: This study aims to determine the forced vital capacity (FVC) and slow vital capacity (SVC) along with other pulmonary functions in Indian diabetic patients for early diagnosis of pulmonary function reduction and to compare the ratios of forced expiratory volume in one second (FEV1) with FVC and SVC (FEV1/FVC and FEV1/SVC) in diabetic patients. Materials and methods: A prospective observational study was carried out in the physiology department for two years after the approval of the institutional ethics committee. The study included 90 type 2 diabetes mellitus patients previously diagnosed by the physician and 90 age and sex-matched controls for spirometric tests. Medspiror having Helios 401 software (Recorders & Medicare Systems Pvt. Ltd., Panchkula, India) was used to assess the pulmonary function in all subjects. A comparison of dynamic pulmonary function parameters among non-diabetic and diabetic groups and non-obese vs. overweight/obese individuals of the diabetic group has been done. FEV1/FVC ratio vs. FEV1/SVC ratio comparison was conducted between the non-obese vs. the overweight/obese group in diabetic patients. Results: A significant variation in FEV1 and FVC was observed in the type 2 diabetic group as compared to the non-diabetic group. However, in the case of type 2 diabetic subjects, FEV1/FVC ratio was almost constant in both BMI groups, whereas the FEV1/SVC ratio increased in the overweight/obese group. Conclusion: Type 2 diabetes mellitus accounts for a predictive factor for worsening pulmonary function. SVC, particularly the FEV1/SVC ratio, can be an earlier diagnostic marker for pulmonary dysfunction in diabetic subjects as this ratio changes even with a constant FEV1/FVC ratio.