Cost analysis and risk factors for interval cholecystectomy after bariatric surgery: a national study.

Background: Besides rate and extent of weight loss, little is known regarding demographic factors predicting interval cholecystectomy (IC) after bariatric surgery and its incremental costs.

Objectives: We aim to identify risk factors predicting IC after bariatric surgery and quantify its associated costs.

Setting: Nationally representative sampling of acute care hospitals across the United States.

Methods: A retrospective cohort study was performed using the National Readmission Database 2010 to 2014. Cox proportional hazard analyses were used to identify risk factors for IC. Linear regression models were constructed to examine associations between cholecystectomy timing and cumulative hospitalization costs.

Results: An estimated national total of 553,658 patients received bariatric surgery during the study period. Of these, 3.3% received concomitant cholecystectomy (CC). After adjusting for bariatric procedure type, age, sex, complication, and length of stay, CC was independently associated with a US$1589 increase in hospitalization cost (95% confidence interval US$1021-2158, P<.01). Of patients that received no CC, only .6% underwent IC during the up to 1-year follow-up. Age<35 (P<.01), female sex (P<.01), and high preoperative body mass index (P = .03) were all risk factors for IC. IC was independently associated with a US$1499 higher cumulative hospitalization cost than CC (P<.01, 95% confidence interval US$844-2154).

Conclusions: Despite the higher absolute cost of IC, its low incidence does not financially justify a routine prophylactic CC approach. In addition, no significant reduction in cholecystectomy-related complications was achieved by performing CC. An individualized approach taking identified risk factors for IC into consideration is recommended when deciding whether to perform prophylactic CC.