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PCORnet study: Procedure type more important than depression status for outcomes

A patients’ decision between whether to have gastric bypass and sleeve gastrectomy (SG) is a more important driver of outcomes than their preoperative depression status, according to the latest findings from the PCORnet Bariatric Study. The study was designed to examine whether depression status before metabolic and bariatric surgery (MBS) influenced five-year weight loss, diabetes and safety/utilisation outcomes in the PCORnet Bariatric Study.

The PCORnet Bariatric Study has previously found that the average percent total weight loss (%TWL) at one-, three- and five-years following surgery was 31.2%, 29.0%, and 25.5% for RYGB, and 25.2%, 21.0%, and 18.8% for SG – with relapse rates among patients with initial diabetes remission increased over time from 8.4% and 11.0% at one year to 33.1% and 41.6% at five years after RYGB and SG.

Approximately 70% of MBS candidates have a history of psychiatric illness and 40% having a lifetime major depressive disorder, the researchers stated that it is important to understand more clearly whether psychiatric comorbidity influences surgical outcomes. They wanted to understand whether surgery was an effect modifier of weight loss, diabetes and adverse health outcomes at one-, three- and five-years after SG and RYGB. They hypothesised that those with depression at baseline would have less weight loss and diabetes improvement and more adverse health events vs. those not diagnosed with depression, regardless of their choice of bariatric operation.


The weight loss cohort included 25,658 patients without depression and 11,213 with depression. RYGB was the more common operation (54% without depression and 61% with depression had a bypass) compared to SG.

Patients with depression were older, predominantly female and White. RYGB patients with depression spent more days in the hospital in the year before surgery than RYGB patients without depression but mean hospital days in the previous year were similar for SG patients with and without depression. The three most common comorbidities were hypertension, dyslipidaemia and sleep pane - regardless of depression diagnosis - and prevalence of each was greater in the depression group. Anxiety was much more prevalent among patients with depression (42%) than those without (11%).

Overall, %TWL was greater for RYGB than SG, and %TWL was slightly larger for patients without depression than those with depression for both operations at one- and three-year post-surgery. BY year five, patients with and without depression had no significant differences in weight loss. The interaction between depression status and operation type was not significant in years one or three but was significant at year five (interaction p=0.04), the between group difference at year five was small (0.42%TWL).

Patients who had RYGB had greater risk of re-operation than those who underwent SG for patients with and without depression. Baseline depression status was not a significant moderator of time to reoperation between the operations (p=0.856), nor did baseline depression status significantly impact risk of revision by operation type (p=0.605).

Risk of endoscopy was greater for RYGB patients than SG patients both with and without baseline depression and those with depression had greater cumulative incidence of endoscopy than those without depression for each procedure. Compared to those without baseline depression, patients with depression had more of an increase in risk of endoscopy if they had SG than RYGB, even though the risk of endoscopy was lower for SG than RYGB overall.

Rates of hospitalisation were greatest for RYGB patients with depression and lowest for SG patients without depression. Risk of hospitalization was greater for RYGB than SG patients with and without baseline depression, although depression status was a significant moderator of time to re-hospitalization between operation type (p=0.046). For all-cause mortality, results were not significant and depression status was not a significant moderator of AE rates between operation type (p=0.415).

“Taken as a whole, it seems that patients’ decision between RYGB and SG is a more important driver of outcomes than their preoperative depression status, and it does not seem that shared decision-making discussions about choosing between RYGB and SG need to be carefully tailored to patients with vs. without baseline depression,” the study authors concluded. “Additional research is needed to examine whether baseline depression severity and treatment patterns or post-operative depression treatment trajectories are more significant predictors of long-term MBS outcomes.”

The findings were reported in the paper, Preoperative Depression Status and 5 Year Metabolic and Bariatric Surgery Outcomes in the PCORnet Bariatric Study Cohort’, published in the Annals of Surgery. To access this paper, please click here


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