RESUMO
BACKGROUND: There is a strong association between obesity and gallstones. However, there is no clear evidence regarding the optimal order of Roux-en-Y gastric bypass (RYGB) and cholecystectomy when both procedures are clinically indicated. METHODS: Based on cross-matched data from the Swedish Register for Cholecystectomy and Endoscopic Retrograde Cholangiopancreatography (GallRiks; 79 386 patients) and the Scandinavian Obesity Surgery Registry (SOReg; 36 098 patients) from 2007 to 2013, complication rates, reoperation rates and operation times related to the timing of RYGB and cholecystectomy were explored. RESULTS: There was a higher aggregate complication risk when cholecystectomy was performed after RYGB rather than before (odds ratio (OR) 1·35, 95 per cent c.i. 1·09 to 1·68; P = 0·006). A complication after the first procedure independently increased the complication risk of the following procedure (OR 2·02, 1·44 to 2·85; P < 0·001). Furthermore, there was an increased complication risk when cholecystectomy was performed at the same time as RYGB (OR 1·72, 1·14 to 2·60; P = 0·010). Simultaneous cholecystectomy added 61·7 (95 per cent c.i. 56·1 to 67·4) min (P < 0·001) to the duration of surgery. CONCLUSION: Cholecystectomy should be performed before, not during or after, RYGB.