The relationship of pre-operative health status to sustained outcome in gastric bypass surgery

The task of sustaining initial weight loss after gastric bypass surgery has been identified as the area of greatest concern in this intervention. The present study investigated the role of good vs. poor pre-operative health as a moderator variable in identifying useful pre-operative predictors of continued weight loss. Follow-up data at a mean of 12.8 months and again at 3.2 years post-operatively were available for 79 patients on 227 interview variables and four psychological assessment instruments. These measures were studied for their success in predicting continued weight loss over the 1-3-year period separately for patients who were in good and in poor general pre-operative health. Previous findings showed that the overall mean simple weight loss to 12.8 months was 45.61 kg, but additional weight loss to 3.2 years was only 0.28 kg. The good and poor pre-operative health groups differed little on these figures. However, the significant predictors of continued weight loss for good-health patients (high anxiety and distress, low self-esteem, poor eating habits, strong expectations of life improvement, and good achievement and coping skills) were quite different from those for poor-health patients (good psychological health and happiness, strong personal support and life satisfaction, good eating habits, and little knowledge about their health). Thus, pre-operative health status served as a powerful moderator in predicting continued weight loss from pre-operative characteristics. These findings offer a means of making more accurate predictions as to which patients are the best candidates for surgery, and also suggest that different psychological and other interventions should be selected according to pre-operative health status.