The risk of visits to the emergency room or hospitalization for acute exacerbations due to chronic obstructive pulmonary disease (COPD) significantly decreases in obese patients after they undergo bariatric surgery, researchers found.
The study, “Reduced Risk of Acute Exacerbation of COPD After Bariatric Surgery: A Self-Controlled Case Series Study,” was published in the journal Chest.
According to estimates, 6% of American adults have COPD, and 35% of those COPD patients are considered obese. In addition to being common among COPD patients, studies have also suggested that obesity leads to a higher risk of acute exacerbations, indicating that obesity may be a risk factor.
Few studies have looked at the impact of weight loss on COPD-associated outcomes. One study reported that patients who lost weight through nonsurgical methods had improved patient outcomes, including exercise tolerance and clinical scores. But little is known about the impact of weight reduction on a COPD comorbidity such as acute exacerbations.
Because bariatric surgery has been shown to be the most effective method for weight loss in patients who are morbidly obese, a number of studies have looked at the outcome of bariatric surgery on health conditions such as asthma, but not on COPD.
Researchers at Massachusetts General Hospital conducted a study to determine whether bariatric surgery in obese patients with COPD would lead to a lower risk of visits to the emergency department and hospitalizations.
They used a population-based emergency department and inpatient sample from California, Florida, and Nebraska, and conducted a case series analysis of 481 patients who were obese, had COPD, and underwent bariatric surgery between the years 2005 and 2011.
The primary goal of the study was to analyze the number of emergency room visits or hospitalizations due to acute exacerbations in COPD (AECOPD). The analysis was conducted based on each patient’s risk during a two-year period, compared to the patient’s risk in the pre-surgery two-year period.
Results indicated that between 13 and 24 months before bariatric surgery, 28% of obese COPD patients visited an emergency room or were hospitalized for AECOPD care. These results were similar for the 12 months immediately preceding the surgery.
But results changed after changed surgery. During the first 12 months post-bariatric surgery, the risk of emergency room visits or hospitalizations declined to 12%. The risk remained low in the 13-24 month period after surgery, at only 13%, suggesting that bariatric surgery reduces the risk for at least two years after the procedure.
The mechanism behind weight loss and a decreased risk of AECOPD is not known.
Researchers suggested that one explanation could be that weight loss reverses the obesity-COPD link, as obesity is linked to lung function in a number of ways. Studies have shown that obesity alters lung mechanics, induces systemic inflammation due to pro-inflammatory mediators derived from fat tissue, alters gut bacteria, increases susceptibility to infections, and is associated with a higher risk of problems such as acid reflux.
Bariatric surgery is known to reduce proinflammatory mediator levels and decrease the incidence of obesity-related health problems. So these may be some of the pathways through which bariatric surgery lowers AECOPD risk.
Overall, the findings support the benefits of weight reduction in COPD disease management, particularly in obese patients.
“The risk of an ED [emergency department] visit or hospitalization for AECOPD substantially decreased after bariatric surgery in patients who are obese. This observation suggests the effectiveness of substantial weight reduction on COPD morbidity,” the team wrote.
The authors urge additional research into the underlying reasons why weight loss leads to a reduction in the risk of hospital visits in COPD patients.