Efficacy of the SF-36 questionnaire in identifying obese patients with psychological discomfort.

Background: The primary endpoint of this study was to assess the association of health-related quality of life (QoL) and the presence of psychopathology. The association of other patients' characteristics and of Cognitive Behavioral Assessment (CBA) scales with quality of life (QoL) was also evaluated.

Methods: 100 consecutive obese patients (WHO grade 2 and 3 obesity), addressed for psychological advice before either invasive or non-invasive treatment of obesity, were investigated. The instruments used were the SF-36 questionnaire (physical and mental component summaries, PCS and MCS), the CBA scales and psychological counselling. The association of PCS and MCS with the presence of psychopathology (Marked or DSM IV discomfort) was assessed by means of logistic regression.

Results: SF-36 PCS was 39.5 (95% CI 37.7-41.3) and MCS 49.8 (95% CI 47.7-51.9). PCS only was significantly lower than the average for the reference normal population. The mean PCS score was similar in the No-Moderate (39.6 (SD 7.6)) and Marked-DSM IV (39.1 (SD 7.6)) groups, with an adjusted odds ratios (OR) of 1.07 (95% CI 0.74-1.55), P=0.706, for 5 points increase in PCS. The mean MCS score was 51.7 (SD 10.3) in the No-Moderate group and 42 (SD 8.1) in the Marked-DSM IV group, with an adjusted OR for 5 points increase in score of 0.63 (95% CI 0.43-0.95), P=0.003.

Conclusions: SF-36, and particularly the MCS component, is a simple tool of easy use that could be utilized for identifying patients needing a specific psychological intervention in severely obese subjects applying for a weight reduction program.