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Effects of depression were clinically small, compared to the choice of operation

Patients with depression undergoing sleeve gastrectomy (SG) and Roux-en-Y gastric bypass had similar weight loss, diabetes and safety/utilisation outcomes to those without depression, researchers from the University of Pittsburgh report, who examined whether depression status before surgery impacted outcomes. They found that the effects of depression were clinically small, compared to the choice of operation.

Using data from the PCORnet Bariatric Study, the investigators examined whether a depression diagnosis in the year before surgery was an effect modifier of weight loss, diabetes and adverse health outcomes at one-, three- and five- years after SG and RYGB.


In total, 25,658 patients without depression and 11,213 with depression were included in the study – 54% received RYGB - with 54% of those without depression and 61% with depression having undergone RYGB, while the others had SG. Patients with depression were older when they underwent RYGB or SG than those without depression, 78% of those without depression and 88% with depression were female, and 58% without depression and 75% with depression were White.


Regardless of depression diagnosis, the three most common comorbidities were hypertension, dyslipidaemia and sleep apnoea, and prevalence of each was greater in the depression group. Anxiety was much more prevalent among patients with depression (42%) than those without (11%).

The diabetes cohort included 2,769 patients with depression and 5,638 patients without depression at baseline. Patients with diabetes were older, with slightly higher BMI with more comorbidities vs. the general weight loss cohort. The mean baseline HbA1c (7.1 to 7.3) and number of diabetes medications prescribed (1.6 to 1.7) were similar across depression groups.


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- years post-surgery. At five years however, 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 (p=0.04). However, the between group difference at year five was small (0.42%TWL).

For both operations, change in HbA1c was not significantly different one year after surgery between those with and without a depression at baseline. At three years follow-up, HbAlc declined more, on average, for SG patients without depression than those with depression (-0.57 and -0.47 percentage points, respectively); however, at five years follow-up, the mean HbA1c decline was similar for SG patients with and without depression.


For RYGB patients, HbA1c declined more, on average, for those with depression than those without at three years (–0.87 and –0.76 percentage points, respectively) and five years (–0.70 and –0.54 percentage points, respectively). Baseline depression status was a significant moderator of glycaemic control across operation types in years three and five (interaction p<0.001 and p=0.038, respectively), where patients with depression had significantly better glycaemic control after RYGB but not after SG.


The rate of remission was higher for RYGB than for SG among those with and without depression (hazard ratios 1.12 and 1.09, respectively), and the relapse rate was lower for RYGB than for SG in patients with and without depression (hazard ratios 0.67 and 0.77, respectively). There was no significant interaction between baseline depression status and operation type for either the remission or relapse outcomes (p=0.571 for remission and p=0.282 for relapse).


The risk of revision surgery was lower for RYGB than SG for patients with and without depression at baseline (hazard ratios 0.72 and 0.79, respectively) although, baseline depression status did not significantly impact risk of revision by operation type (p=0.605).


For all-cause mortality, results were not significant, suggesting no difference in risk between operation type and no impact of depression status. Rates of any 30-day Major Adverse Event were lower for SG than RYGB, and for both operations, AE rates were greater for those with depression than without. 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” they concluded.


They called for additional research examine whether baseline depression severity and treatment patterns or post-operative depression treatment trajectories are more significant predictors of long-term surgical outcomes.


The outcomes 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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