Long-term improvements in pulmonary function 5 years after bariatric surgery.

Hewitt, Stephen; Humerfelt, Sjur; Søvik, Torgeir T; Aasheim, Erlend T; Risstad, Hilde; Kristinsson, Jon; Mala, Tom

BACKGROUND Obesity is associated with reduced pulmonary function. We evaluated pulmonary function and status of asthma and obstructive sleep apnoea syndrome (OSAS) before and 5 years after bariatric surgery. METHODS Spirometry was performed at baseline and 5 years postoperatively. Information of asthma and OSAS were recorded. Of 113 patients included, 101 had undergone gastric bypass, 10 duodenal switch and 2 sleeve gastrectomy. RESULTS Eighty (71%) patients were women, mean preoperative age was 40 years and preoperative weight was 133 kg in women and 158 kg in men. Five years postoperatively, weight reduction was 31% (42 kg; p < 0.001) in women and 24% (38 kg; p < 0.001) in men. Forced expiratory volume in 1 s (FEV1) increased 4.1% (116 ml; p < 0.001) in women and 6.7% (238 ml; p = 0.003) in men. Forced vital capacity (FVC) increased 5.8% (209 ml; p < 0.001) in women and 7.6% (349 ml; p < 0.001) in men. Gender and weight loss were independently associated with the improvements in FEV1 and FVC. At follow-up, FEV1 had increased 36% of the difference towards the estimated normal FEV1, and there was a corresponding 70% recovery of FVC. These improvements occurred despite an expected decline in pulmonary function by age during the study period. Of the asthmatics and OSAS patients, 48 and 80%, respectively, were without symptoms 5 years postoperatively. CONCLUSIONS Pulmonary function measured with spirometry was significantly improved 5 years after bariatric surgery, despite an expected age-related decline during this period. Symptoms of asthma and OSAS also improved.