Patients undergoing bariatric surgery experience significant improvement in their quality of life and a high level of patient satisfaction, whether or not they have comorbid mental health disorders.

That's the conclusion of researchers at the University of Michigan, who recently analyzed data from the Michigan Bariatric Surgery Collaborative (MBSC), a prospective registry of patients undergoing bariatric surgery in a consortium of Michigan hospitals.

The MBSC enrolls nearly 6,000 patients annually, and participating hospitals and bariatric surgeons submit data on all patients undergoing both primary and revisional bariatric procedures, including open and laparoscopic gastric bypass, adjustable gastric band, sleeve gastrectomy, and biliopancreatic diversion with duodenal switch.

Data are collected on patient characteristics, comorbidities, and outcomes, with further information obtained from annual surveys. For this study, the researchers identified 25,469 patients undergoing a primary (nonrevisional) bariatric surgery procedure between June 2006 and December 2010. Baseline and follow-up surveys at one, two, and three years were completed by 66 percent, 31 percent, 22 percent, and 12 percent, respectively.

Psychiatric disorders were reported in 11,687 (46 percent) of the patients and include depression (41 percent), anxiety (15 percent), bipolar disorder (2 percent), eating disorder (0.4 percent), and substance abuse (0.8 percent). Patients with psychiatric diagnoses had higher rates of comorbid disease and mobility limitations, were more likely to be female, and were less likely to have private insurance than patients without a psychiatric diagnosis.

The researchers pointed out that eating disorders and substance abuse have been identified in similar patient populations in other studies, and they hypothesize that "these discrepancies suggest that these disorders were poorly captured in the MBSC clinical registry." Jonathan Finks, M.D., an assistant professor in the Division of Minimally Invasive Surgery at the University of Michigan Health System's Taubman Health Care Center and a study co-investigator, explained that "the diagnoses were obtained from abstraction of the medical record and not from in-depth patient interviews, which would be more likely to identify these disorders."

Underlying psychiatric disease did not affect long-term quality of life, although it did have a somewhat negative influence on patient satisfaction. Patients previously diagnosed with depression experienced a substantial decline in the use of antidepressants after surgery—rates of antidepressant use among patients with depression declined substantially at one year following bariatric surgery and remained stable up to three years after surgery.

The researchers found that psychiatric disorders are common among morbidly obese patients undergoing bariatric surgery, but that overall, outcomes from surgery are comparable between those with and without psychiatric disease.

"A more in-depth assessment of the impact of obesity on psychiatric disorders is certainly warranted," Finks told Psychiatric News. "We looked at short-term results, and further study will be needed to evaluate the long-term effects of bariatric surgery on psychiatric illness in obese patients. However, a more indepth assessment of the impact of obesity on psychiatric disorders could easily be accomplished within the construct of our collaborative."

The efforts of the MBSC are funded through Blue Cross/Blue Shield of Michigan.

David Sarwer, Ph.D., an associate professor of psychology at the University of Pennsylvania School of Medicine presented the results of this study at the annual meeting of the American Society for Metabolic and Bariatric Surgery in Orlando, Fla., in June. An abstract of the results was published in that meeting's proceedings.