Weight-loss surgery is currently only offered to patients who exceed a certain BMI. However, surgical intervention could improve the health of many more people. This is shown by the Swedish Obese Subjects study carried out at the Sahlgrenska Academy, University of Gothenburg, Sweden, involving 104 patients who were operated on despite their BMI being "too low". As a result, the risk of developing diabetes was reduced by 67 percent.
In order to meet the current selection criteria for weight-loss surgery, Swedish patients must have a body mass index (BMI) above 40 for healthy patients, or above 35 in combination with other risk factors such as type 2 diabetes.
However, these selection criteria have not been devised in a scientific manner, and need to be improved. This is the opinion of researchers at the Sahlgrenska Academy, University of Gothenburg, who have shown in a new study that weight-loss surgery also offers significant health benefits for patients who do not meet today's criteria.
In the study, which has been published in Diabetes Care, the researchers from Gothenburg have monitored 104 patients who had weight-loss surgery before the current criteria were established, and who would not have been offered the operation today. The study shows that, 15 years after the procedure, these patients had a 67 percent lower risk of developing diabetes compared with a control group who were not operated on.
"The effect was the same as for patients who meet the current criteria," explains researcher Kajsa Sjöholm from the Sahlgrenska Academy, University of Gothenburg. "In other words, there is no proof that weight-loss surgery has a greater preventive effect against diabetes for patients who exceed today's BMI limit than for those who don't."
The study also shows that weight-loss surgery reduces the risk factors for cardiovascular disease among patients who are not currently eligible for this surgery.
With reference to previous results published in the SOS study at the University of Gothenburg, which showed that weight-loss surgery generally results in a long-lasting reduction in weight and reduces the risk of diabetes, heart disease, stroke, cancer and premature death, the researchers from Gothenburg believe that today's selection criteria should be re-evaluated.
According to the researchers, strict BMI limits can lead to patients with a high risk of future disease who would benefit from treatment being denied surgery. Previous research findings show that the selection can be improved by analysing patients' insulin and glucose values.
The article "Evaluation of Current Eligibility Criteria for Bariatric Surgery: Diabetes prevention and risk factor changes in the Swedish Obese Subjects (SOS) study" was published in Diabetes Care on 28 January.
ABOUT THE SOS STUDY
The Swedish Obese Subjects (SOS) study has monitored 4,047 obese patients for up to 20 years. Of these, half underwent weight-loss surgery and half were treated by the Swedish primary healthcare service. The study has contributed towards increased knowledge of the long-term effects of weight-loss surgery, and the researchers have published a number of internationally noted reports showing that weight-loss surgery prevents diabetes, cardiovascular disease and cancer, and reduces the risk of premature death.
Lena Carlsson, Professor at the Institute of Medicine, Sahlgrenska Academy,
+46 (0)70 679 1154
Kajsa Sjöholm, Docent at the Institute of Medicine, Sahlgrenska Academy,
+46 (0)73 368 0308