Publication:

A prospective study of pulmonary function test in obese patients

Background Obesity is considered to affect the respiratory functions. The objective was to study the pulmonary function test and its correlation with smoking, hypertension and diabetes in obese patients with Body Mass Index (BMI) ≥30 kg/m2Methods: A cross sectional study was done on 100 patients with age >18 years and Body Mass Index (BMI) ≥30 kg/m2 in the Department of Medicine, GR Medical College, Gwalior during the period between July 2013 to November 2014. After thorough history and clinical examination of all the selected patients, they were subjected to routine investigation and spirometry (Pulmonary function test). Pulmonary Function Test (PFT) was performed by using UNI-EM spirometer.

Results Out of 100 patients, 37% were in the age group of 41-50 years followed by 27% in 31-40 years and there was a female predominance (53%). Abnormal PFT was found in 58% patients, out of which the commonest pattern was restrictive (32%) followed by mixed pattern (26%). Among females with abnormal PFT restrictive and mixed type pattern were seen in 32% and 18.9% respectively whereas among males 32% and 34% had restrictive and mixed pattern of abnormal PFT respectively. It was found that abnormal PFT pattern was directly proportional to increase in BMI. The mean Forced Vital Capacity (FVC) was 77.76 ± 15.56 L, mean Forced Expiratory Volume in one second (FEV1) was 77.97 ± 17.40 L while mean FEV1/FVC ratio was 105.44 ± 7.85 in the study population. Most common PFT pattern seen in smokers was mixed type (55%). Among hypertensive patients 42.1% had normal PFT.

Conclusions More than half of obese patients were having abnormal PFT in our study, and the increase in BMI was associated with increase in abnormal PFT pattern. The most common abnormal function was restrictive pattern as reflected by decreased mean FVC, FEV1 and increased FEV1/FVC ratio. There was no correlation between hypertension and pulmonary function test in obese; similarly no correlation was seen between diabetes and PFT in obese.