Correlation of body mass index and pulmonary hypertension in patients with obstructive sleep apnoea

Abstract

Obstructive sleep apnoea has very strong association with both body mass index and pulmonary hypertension. There is a paucity of data to relate BMI and PH in patients with OSA. To see the relation between body mass index and pulmonary hypertension in patients with obstructive sleep apnoea. Patients with symptoms of OSA were screened for polysomnography by using STOP-BANG criteria. 100 patients with AHI ≥5 with symptoms of obstructive sleep apnoea and AHI ≥ 15 without symptoms of obstructive sleep apnoea were selected for other investigations. Neck circumference was measured and BMI was calculated to estimate the severity of obstruction. PFT and chest X-ray were done to rule-out other respiratory illnesses. 2D-echocardiography was done for screening of pre-existing structural cardiac anomaly or any raise in pulmonary artery pressure. MRI neck was done to check neck muscles status. Out of 100 patients in study group 10% (n=10) had mild, 12% (n=12) had moderate and 78% (n=78) had severe OSA. Most of the patients belonged to overweight (52%) and obesity stage 1 (34%) groups. 10% and 2% of the patients belonged to obesity stage 2 and severe obesity groups respectively. Only 2% of the patients were healthy and none of the patients were underweight. PH was present in 24% (n=24) of cases, mild (n=10) and moderate (n=10) PH each were 10% and severe (n=4) PH was present in 4% of the cases. 100% of the patients with severe obesity had pulmonary hypertension. Most of the patients with PH belonged to Obesity grade 1 and overweight groups, whereas none of normal BMI patients had PH. Body mass index has indirect relation with pulmonary hypertension. In our study, we found that pulmonary hypertension was present only in overweight and obese patients. Whereas, none of the patients with normal BMI had pulmonary hypertension.