A multicentre study conducted in 16 hospitals of the state has evaluated the long-term efficacy of respiratory support systems in patients with obesity hypoventilation syndrome. In this study, published in https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(18)32978-7/fulltext The Lancet magazine, participatedthe doctors Sergi Martí Beltran, Odile Romero, Mercedes Pallero and Marian Ramon, researchers from the Vall d'Hebron Research Institute's Pneumology Research Group (VHIR).Obesity hypoventilation syndrome is a respiratory disease that affects people with obesity and causes low levels of oxygen and too high levels of carbon dioxide in the blood. This is caused by an affliction called hypoventilation (when the inhalation and exhalation of the air of the lungs are not performed correctly) and obstructive sleep apnea syndrome. Patients with hypoventilation syndrome due to obesity are at higher risk of respiratory and cardiovascular complications as well as hospital admission."In this study, the two most common respiratory therapies that these patients need have been compared: continuous positive pressure on the respiratory system (CPAP) and non-invasive ventilation. It is the first time that a study of these characteristics is carried out in the long term, "explains Dr. Sergi Martí.The randomized, multicentre, open and controlled clinical trial was carried out in 16 hospitals of the State. Between May 2009 and March 2013, 215 patients between the ages of 15 and 80 were recruited who had been referred to the Pneumology service for tertiary hospital centers with hypoventilation syndrome due to untreated obesity and an index of apnea-hypopnea of 30 or more events per hour.The primary objective of the study was to analyze the number of days of hospitalization among patients treated with CPAP and those who followed the non-invasive ventilation therapy. In the first group, the average number of days of hospitalization per year was 1.63 days, and in the second group of 1.44 days. Therefore, there were no significant differences.The secondary objectives were to evaluate the use of other hospital resources (for example, visits to the emergency department, hospital admissions and admissions to the ICU), cardiovascular events, mortality due to any cause, blood pressure, balance of arterial blood gases (that is, PaCO2, PaO2, bicarbonate and pH), the functional respiratory results (that is, FEV1 and FVC), a 6-minute walk test (6-MWD) and quality of life related to the Health.The researchers observed that, in the long term, there were no significant differences in any of these parameters between the noninvasive ventilation therapy and the positive continuous pressure of the airway.In addition, no significant differences were observed in daytime sleepiness and the associated symptoms of hypoventilation syndrome due to obesity."On the other hand, a higher level of adherence to non-invasive ventilation or the continued positive pressure of the airways was associated with fewer days of hospitalization and a reduction in the use of hospital resources and mortality" , says Dr. Martí.In conclusion, noninvasive ventilation and continuous positive pressure on the respiratory tract seem to have a similar long-term efficacy and given that CPAP is cheaper than non-invasive ventilation, it could be the first line treatment in stable patients with syndrome hypoventilation of obesity and serious obstructive sleep apnea.