Changes in fat-free mass and muscle mass at 6 and 12 months after biliopancreatic diversion with duodenal switch surgery.

BACKGROUND

Bariatric surgery is associated with concomitant loss in both fat and muscle masses. Literature on muscle composition/quality after bariatric surgery is limited.

OBJECTIVES

To measure and compare the changes in fat-free mass with the changes in muscle composition after biliopancreatic diversion with duodenal switch surgery (BPD/DS).

SETTING

Bariatric surgery is associated with concomitant loss in both fat and muscle masses. Literature on muscle composition/quality after bariatric surgery is limited.

METHODS

Forty patients underwent BPD/DS and 22 patients are considered as controls. Bioelectrical impedance analysis (body composition) and computed tomography scan at the midthigh and abdominal levels (muscle composition) were performed at baseline, 6, and 12 months.

RESULTS

At 6 and 12 months, the BPD/DS group displayed significant reduction in weight (12 months: -46.6 ± 13.5 kg) and fat-free mass (12 months: -8.2 ± 4.4 kg; both P < .001). A significant reduction in abdominal (-15 ± 8%, P < .001) and midthigh muscle areas (-18 ± 7%, P < .001) was observed during the first postoperative 6 months, followed by a plateau after 6 months (abdominal: -1 ± 5%, midthigh: -1 ± 4%, both P > .05). At 6 months, both midthigh fat-infiltrated muscle (-22 ± 10%, P < .001) and normal-density muscle (-16 ± 9%, P < .001) areas decreased. Further reduction at 12 months was only observed in the fat-infiltrated muscle (-11 ± 8%, P < .001) in comparison with an increase in the normal-density muscle area (5 ± 8%, P = .001). There was no significant change for the control group.

CONCLUSIONS

Reduction in muscle, assessed with computed tomography scans, occurs mostly during the first 6 months postoperatively after BPD/DS. Focus on muscle quantity as well as quality, using precise imaging methods, instead of quantifying total body lean mass, is likely to provide better assessment in body content modulation after BPD/DS.