Measuring outcomes following bariatric surgery: weight loss parameters, improvement in co-morbid conditions, change in quality of life and patient satisfaction.

Restrictive and particularly malabsorptive bariatric operations achieve significant sustained weight loss. Results from different operations have been difficult to compare. The aims of this review are: 1) to indicate the limitations of outcomes reported as weight-related parameters; 2) to document some of the patient characteristics that impact weight loss; 3) to assess the literature documenting improvement in obesity-related medical conditions; and 4) to review studies that quantitate changes in health-related quality of life (QoL). Weight-related parameters such as body mass index and % excess weight inconsistently correlate with body fat. Direct determination of body fat with bioelectric impedance may offer more reliable outcome parameters. Patient characteristics such as gender, age, weight, body mass index, ethnicity, race and socioeconomic status affect weight loss following bariatric operations. Improvements in co-morbid conditions are poorly documented in many studies. Standardized instruments that assess health-related QoL have shown differing values. SF-36 has given inconsistent results following bariatric operations. Both BAROS and IWQoL-Lite have demonstrated significant improvements after surgery. Bariatric surgeons have rarely used patient satisfaction as an outcome parameter. This review suggests that bariatric operations should be judged by change in fat mass or fat mass index, improvement in obesity-related medical conditions, change in health-related QoL as judged by standardized instruments, and level of patient satisfaction. In addition, surgeons should characterize their study population and report outcomes for sub-populations.