The influence of psychological factors on the outcome of Gastric Bypass operation

Gastric bypass surgery has been shown to be an effective treatment against
morbid obesity. Research shows that after a gastric bypass operation overweight
decreases while health and quality of life increases significantly. Although
the majority of the patients clearly profit from the operation there is also a
small but considerable portion of the patients who show less improvements
post-operatively. Insight in the determinants of post-operative outcomes is
important as it may help optimize care and improve the outcomes of a gastric
bypass operation even further.
Although surgical and metabolic factors may play a role in post-operative
outcomes, psychological factors may also help to explain individual differences
in weight loss and quality of life post-operatively. A gastric bypass operation
enforces behavioral changes in patients which may be experienced as a serious
life-event and requires psychological resilience. Although most patients will
be able to adapt to the changes imposed by the operation, other patients may be
less able to change their diet and exercise behavior and show less improvements
in weight loss and quality of life over time. This is supported by research
showing that patients with two or more psychiatric disorders profit less from a
gastric bypass operation as they report less weight-loss, poorer quality of
life post-operatively and worse compliance. These studies are however limited
as they (1) do not follow patients over time and (2) are not able to explain
the differences in post-operative outcomes sufficiently.

The purpose of the proposed research is to investigate which patients may
report less weight loss and worse quality of life in the first two years after
a gastric bypass operation. Moreover, the proposed study will offer information
why and when these less than optimal outcomes may evolve. The main hypothesis
states that in addition to medical factors (co-morbidity, initial weight)
psychological factors such as life-time and current psychopathology and
personality characteristics (independent variables) will be associated with
weight loss and quality of life (dependent variables) in the first two years
after a Gastric Bypass operation. The second hypothesis states that the
association between psychological factors and gastric bypass outcomes will be
mediated by medical complications, compliance to diet and exercise
recommendations, coping, social support and stressors.

In this 3 year prospective study we will include 100 patients receiving a
gastric bypass operation in Slotervaart Hospital. These patients will be
followed over a 24 month period using an internet based data collection and
monitoring system. To be able to investigate when and why suboptimal gastric
bypass outcomes may evolve patients will be requested (by SMS, email) to
complete digitalized questionnaires at 1 month, 3 months, 6 months, 12 months,
18 months and 24 months after the operation. Moreover, patients will be
screened pre-operatively. A pre-surgical assessment is standard in the
appraisal process and consists of a questionnaire and semi-structured interview
investigating among other things, weight (BMI), preoperative diet and exercise
habits, co-morbidity, sociodempgraphics, lifetime and current psychopathology.
For the proposed study a few questionnaires will be added assessing personality
characteristics and quality of life preoperatively. Postoperatively, weight and
quality of life as well as medical complications, compliance to dietary and
exercise recommendations, coping, social support and current stressors will be
assessed six times in a two year period. This data collection schedule will be
long and intensive enough to detect and explain variations in gastric bypass
outcomes.

The aim of a gastric bypass operation is to improve health and quality of life
in patients suffering from morbid obesity by reducing their weight. To optimize
the outcome of a gastric bypass operation a perceptive that takes psychological
factors into account may be vital. However, the gravity of the obesity and the
health improvements imposed by the surgery usually do not allow much attention
for psychological factors pre-operatively which may leave psychological
risk-factors undetected and untreated. This may in turn result in poorer weight
loss, worse quality of life, more healthcare utilization, reduced compliance
and increased costs. Therefore is important to have notion, at an early stage,
which patients may experience less optimal outcomes after a gastric bypass
operation and why. In order to be able to answer these questions patients will
be asked to complete questionnaire six times in a two year period with a total
time burden of approximately 3 hours. Moreover, patients will be assessed
pre-operatively using a semi-structured interview (45 minutes) and
questionnaires (60 minutes). The total time burden pre-operatively will be
approximately 1hour and 45 minutes which of which 1hour and 15 minutes is part
of normal preoperative assessment.
Moreover, in the present study instead of paper-and-pencil measurements, the
use of an internet based data collection and monitoring system (*Zorgportaal*)
is proposed. Given the longitudinal design and of the study the multiple
assessment points a computerized system that allows patients to complete
questionnaires at home will be less demanding for patients as well as the
researcher team and may minimize drop-out. .
In the future such a system may also help to optimize clinical practice. First,
a longitudinal internet based monitoring and data collection system meets the
wishes of bariatric surgery guidelines to offer systematic long-term follow-up.
Secondly, it may to help organize postoperative care more effectively and
efficiently by identifying those in need of additional (medical/
dietetic/psychological) care at an early stage. That is, patients reporting
scores on the post-operative assessments that warrant clinical attention may be
invited by appointed members of the Multidisciplinary team (surgeon, dietician,
psychologist, internist) for additional diagnostics and, when needed,
treatment. This early detection may alleviate the outcome of Gastric bypass
surgery, especially for those patients with a more extensive psychiatric
history.