Assessment of Pulmonary Function and Clinical Features, and Their Comparison Between Obese and Non-Obese Patients of Bronchial Asthma

Abstract

BACKGROUND Asthma is a heterogeneous disease, usually characterized by chronic inflammation. It is characterised by history of respiratory symptoms such as wheeze, shortness of breath, chest tightness and cough that vary over time and in intensity, together with variable expiratory airflow limitation. 1 Obesity may be defined as an abnormal growth of the adipose tissue due to an enlargement of fat cell size or an increase in fat cell number or both. 2 Asthma with obesity is one of the phenotypes of asthma where patients will have multiple consequences related to excess adipose tissue, including mechanical or physiologic effects on lung function and the airways as well as changes in the immune response and metabolic effects. Our study is a hospital based cross sectional observational study to assess the pulmonary function, clinical profile and its correlation between obese and non-obese bronchial asthmatic patients. METHODS This was an observational study of stable obese and non-obese bronchial asthma patients undergoing pulmonary function test on inpatient or outpatient basis in Department of Pulmonary Medicine, J.J.M. Medical College, Davangere. The study was carried out on 100 patients with bronchial asthma (50 obese and 50 non-obese patients). Detailed history was obtained, physical examination was done along with correlation of pulmonary function and clinical profile. Sample size was taken for convenience. RESULTS In this study, out of 100 patients 55% were males, and 45% were females with higher total cholesterol and triglycerides in obese asthmatics compared to non-obese asthmatics. The most common symptoms were breathlessness followed by cough and wheeze. In this study, it was found that breathlessness, cough, wheeze are more common in obese asthmatics than non-obese asthmatics. There was significant difference of waist circumference (W.C.), hip circumference (H.C.) and waist to hip ratio (W.H.R.) between obese and non-obese asthmatics. Hypertension and diabetes mellitus more prevalent in obese group than non-obese. FVC, FEV1, and FEF25-75 % values were reduced in obese asthmatics compared to non-obese asthmatics in contrast to FEV1/FVC which was higher in obese asthmatics compared to non-obese asthmatics. It was observed that increased in BMI causes impaired pulmonary function. CONCLUSIONS The increasing prevalence of asthma and obesity has suggested an association between the two. The most common symptoms observed in this study were breathlessness, cough and wheeze. PR (Pulse Rate) SBP (Systolic Blood Pressure), DBP (Diastolic Blood Pressure), RR (Respiratory Rate), TLC (Total Leucocyte Count), AEC (Absolute Eosinophil Count), LP (Lipid Profile) were higher in obese asthmatics. Diabetes mellitus and hypertension were more prevalent in obese asthmatics. FVC, FEV1 are decreased in obese asthmatics but the amount of reversibility is more for non-obese asthmatics. It was also observed that increased BMI causes impaired pulmonary function.