The role of obesity severity in Minnesota multiphasic personality inventory-2-restructured form prediction of 12-month bariatric surgery outcomes.

BACKGROUND

The Minnesota Multiphasic Personality Inventory-2 Restructured Form (MMPI-2-RF) has been widely used in bariatric surgery samples. However, questions remain regarding its utility when predicting changes in body mass index over time following bariatric surgery.

OBJECTIVES

Examine whether MMPI-2-RF scales differentially predict 12-month changes in body mass index (BMI) following bariatric surgery when comparing patients with Class III or higher versus Class II or lower obesity.

SETTING

Military hospital in the Northwestern United States.

METHODS

This retrospective study evaluated data from 193 bariatric surgery patients who completed the MMPI-2-RF as part of presurgical evaluation requirements. Hierarchical linear modeling was used to predict body mass index over a 12-month postsurgical period based on MMPI-2-RF scales. Loss to follow-up rate was 30% during this period.

RESULTS

Among patients with Class II or lower obesity, the Symptom Validity, Adjustment Validity, Response Bias, Cynicism, Aggression, Stress/Worry, and Anger Proneness scales showed a significant relationship to BMI after bariatric surgery. Among patients with Class III or higher obesity, the Infrequent Psychopathology Responses, Emotional / Internalizing Dysfunction, Ideas of Persecution, Multiple Specific Fears, and Inefficacy scales showed a significant relationship to body mass index after bariatric surgery.

CONCLUSIONS

Certain MMPI-2-RF scales may have better utility in predicting bariatric surgery outcomes based on the patient's obesity severity. The interaction of metabolic and personality factors may play a significant role in weight change following bariatric surgery.