Post robotic investment: Cost consequences and impact on length of stay for obese women with endometrial cancer

Introduction: The aim of the study was to investigate whether robotic-assisted surgery is associated with lower incremental resource use among obese patients relative to non-obese patients after a Danish nationwide adoption of robotic-assisted surgery in women with early-stage endometrial cancer. This is a population-based cohort study based on registers and clinical data. Material and methods: All women who underwent surgery (robotic, laparoscopic and laparotomy) from 2008 to 2015 were included and divided according to body mass index (<30 and ≥30). Robotic-assisted surgery was gradually introduced in Denmark (2008–2013). We compared resource use post-surgery in obese vs non-obese women who underwent surgery before and after a nationwide adoption of robotic-assisted surgery. The key exposure variable was exposure to robotic-assisted surgery. Clinical and sociodemographic data were linked with national register data to determine costs and bed days 12 months before and after surgery applying difference-in-difference analyses. Results: In total, 3934 women were included. The adoption of robotic-assisted surgery did not demonstrate statistically significant implications for total costs among obese women (€3,417; 95% confidence interval [CI] −€854 to €7,688, p = 0.117). Further, for obese women, a statistically significant reduction in bed days related to the index hospitalization was demonstrated (−1.9 bed days; 95% CI −3.6 to −0.2, p = 0.025). However, for non-obese women, the adoption of robotic-assisted surgery was associated with statistically significant total costs increments of €9,333 (95% CI €3,729–€1,4936, p = 0.001) and no reduction in bed days related to the index hospitalization was observed (+0.9 bed days; 95% CI −0.6 to 2.3, p = 0.242). Conclusions: The national investment in robotic-assisted surgery for endometrial cancer seems to have more modest cost implications post-surgery for obese women. This may be partly driven by a significant reduction in bed days related to the index hospitalization among obese women, as well as reductions in subsequent hospitalizations.