Background  

Weight loss after bariatric surgery varies between patients, and predicting the extent thereof is often inaccurate. The aim of this study was to assess the potential of preoperative plasma leptin and body weight in predicting the maximum weight loss within 2 years after Roux-en-Y gastric bypass (RYGBP).

Methods  

The study comprised 68 subjects (39 women, 29 men; mean age 36.4 ± 10.2 years, body weight 130.3 ± 24.8 kg, BMI 44.4 ± 6.8 kg/m²) undergoing RYGBP who were followed for 2 years. Baseline and maximum follow-up plasma leptin and weight were assessed.

Results  

Mean maximum weight reduction of 50.5 ± 19.1 kg (38.0 ± 9.0%, range 24 – 100 kg) was noted at 15 ± 4 months after RYGBP. Baseline plasma leptin was 37.9 ± 14.5 ng/ml, and decreased to 17.4 ± 8.1 ng/ml (P < 0.001) at maximum weight reduction. No significant correlation between baseline plasma leptin and absolute or relative weight reduction or minimum body weight achieved was noted. No significant plasma leptin threshold which would be predictive for any consistent extent of weight loss was found. However, baseline body weight was a strong determinant of minimum body weight attained (r = 0.67; P < 0.01) and of maximum absolute weight reduction (r = 0.81; P < 0.01).

Conclusion  

Preoperative plasma leptin concentration cannot be used as a predictor of weight reduction following RYGBP. Preoperative body weight is a reliable predictor of post-RYGBP weight loss.