Assessment of Lung Functions by Spirometry in Diabetics with no Respiratory Complaints

Abstract

Background and objectives: Diabetes produces a number of biochemical, morphological, and functional abnormalities that can affect the kidney, cardiovascular and neurological systems, as well as the skin and liver by altering collagen and elastic fibers. Diabetics' lungs show histological alterations such as thicker alveolar epithelium and pulmonary capillary basal lamina, resulting in decreased pulmonary elastic rebound and lung volume. Spirometry is a test to assess lung function in various respiratory diseases. The aim of our study was to assess the lung function by spirometry in patients with diabetes mellitus with no respiratory complaints and compare with lung function among healthy controls. Our additional intention was to find out the association between duration of disease and lung function impairment, if any, and further to compare impairment in lung function, if any, between diabetic patients with controlled and uncontrolled glycemic status. We also compared lung function between diabetic patient with diabetic complications and diabetic patient without diabetic complications.

Material and methodology: This cross-sectional observational study was conducted in Department of Medicine. Patients attending the Medicine OPD for Diabetes Mellitus with no respiratory complaints were interviewed. After application of appropriate inclusion and exclusion criteria, qualifying subjects underwent detailed history, clinical examination, routine investigations and spirometric evaluation. A total of thirty cases were included in the study. A total of thirty age and sex matched apparently healthy subjects were also taken as controls.

Observation and results: In our study, FEV1 (Measured Value) was normally distributed and, therefore, student t-test (2 tailed) was used to analyze the difference between the groups. No statistically significant difference was found between the cases and controls (p value = 0.437). FVC was also normally distributed and, therefore, student t-test (2 tailed) was used to analyze the groups. No statistically significant difference was found between the cases and controls (p value = 0.331). FEV1/FVC Ratio (Measured) was not normally distributed and therefore a non parametric test was used to analyze the groups. No statistically significant difference was found between the cases and controls (p value 0.336). The Mean ± SD of FEV1 (Measured Value) was 2.55 ± 0.66 for the diabetic subjects with duration 0- 5 Years, 2.21 ± 0.69 for those with duration 6-10 Years and 2.53 ± 0.67 for those with duration >10 years. No statistically significant difference was found between the three groups (p value 0.433) as assessed by One way ANNOVA. The Mean ± SD of FVC (Measured Value) was 3.19 ± 0.82 for diabetics with duration 0- 5 Years, 2.79 ± 0.81 for those with duration 6-10 Years and 3.29 ± 0.93 for those with duration >10 years. Again, no statistically significant difference was found between the 3 groups (p value 0.523) as assessed by One way ANNOVA. The Mean ± SD of the FEV1/FVC (Measured Value) was 0.8 ± 0.05 for the subjects with diabetes duration 0- 5 Years, 0.79 ± 0.07 for those with duration 6-10 Years and 0.78 ± 0.04 for those with duration >10 years. No statistically significant difference was found between the 3 groups (p value 0.563). On basis of spirometry interpretation out of 30 cases, 2 patients (6.67%) were found to have a restrictive pattern of airway disease. On other hand, all controls were found to have a normal pattern of spirometry. No statistically significant difference between spirometric parameters of FEV1, FVC, FEV1/FVC, FEF25-75% was found between diabetic subjects with and without complications abd among diabetics with controlled and uncontrolled diabetes.

Conclusion: This study shows that spirometric variables FEV1, FVC, FEV1/FVC and FEF 25-75% were not different between diabetic subjects who were not having respiratory complaints and healthy controls. Also, duration of diabetes, diabetic control and presence of other diabetes related complications do not affect the lung function among diabetics. So, unlike eye and kidney, there is no need for screening for lung function abnormality among diabetics with no respiratory complaints.